Dipper has known Bill for a very long time. Seven years have passed since their first meeting and a lot has happened. Bill has tried to bring about the Apocalypse and has gained a human body in the process. It's a very unique body – the most distinguishing feature of which is his blond hair. An accurate description of it would be to out rightly call it yellow or even gold. In any case, Bill's plan was foiled and most of his power was taken away.
This being said, Bill still hangs around and Dipper thinks it might have started off as out of spire but is has likely now evolved to something else – something more. The demon now occasionally travels beyond Gravity Falls and alternative dimensions to Dipper and Mabel's home. He mostly bothers Dipper at night, when he's trying to sleep or do other things. Bill was the biggest pain in the ass when Dipper was first hitting puberty and exploring his body. He would tease him about his voice cracks, blemishes and spontaneous boners. Bill is now just a regular pain in the ass.
Dipper is currently nineteen years old and he's far wiser and more observant than he's ever been while growing up. He notices the amount of sexual comments and teases Bill directs to him. He notices the occasional glazed gazes and dilated pupils. He notices the hints of sincerity in Bill's voice when he jokes about certain things. Dipper wonders how the demon would react if he ever took him up on those offers.
Dipper is sitting in his bed. He's got his laptop on his knees and his earphones are not plugged in because he's home alone. He's watching porn and getting off at his leisure while alternating between watching two men, two women and a man and a woman fuck. He's found some very lewd videos that are very much to his tastes. He's glad he's finally able to take the time to do this. Lord knows it's been a very long time since he's last satisfied his needs.
And yet, he knows this peace won't last for much longer because Dipper already feels a second presence in his room. He knows exactly who it is because he has experienced this feeling many times before. At this point, he's just waiting for his voyeur to manifest himself and act as though he hasn't been watching for the last couple of minutes. A part of Dipper hopes he can finish himself before said moment but as soon as the thought crosses his mind—
"My, my," Bill chuckles and suddenly appears floating at the other end of the bedroom, "Those teenage hormones still acting?"
"Enjoy the show, Bill?" Dipper smirks and pauses the video just after listening to a particularly obnoxious moan.
Bill blushes and frowns at the comment. He floats a bit closer as Dipper tucks his still erect cock back into his boxers – he does have a level of reservation, even in regards to someone he knows watches him masturbate more times than not. "I wasn't watching!" Bill defends and his tone is a bit too defensive to be believable, "I just got here!"
"Then to what do I owe this pleasure?" Dipper asks as he grabs a few tissues from his Kleenex box to wipe the precum from his hand. He smiles at how calm he feels. The first times Bill pulled this stunt, he threw the biggest fit and felt impossibly embarrassed.
"I don't understand you humans,' Bill sidetracks the same way he does when he's about to do one of three things – tease Dipper about his hormones, his dick or jokingly offer himself sexually. Dipper already knows which of the three this conversation is heading towards, "You're all so accentuated on having sex or anything similar."
"Primal needs." Dipper says dismissively and leans back comfortably with his hands on his lap as he waits.
Bill notices how Dipper fails to put in an effort to humour him. He inches closer to the point of being in the centre of the room and relatively close to the bed.
"Your needs don't revolve around spreading your seeds aimlessly." Bill argues pointlessly because Dipper obviously doesn't care, "Your primal need is to reproduce."
"Guess humans change." Dipper shrugs in disinterest and forces himself not to smirk. He's going to let this play out the same way it always does except, this time, Dipper might actually opt for a different ending. He's feeling in the mood for it.
Bill inches closer some more but he's still out of Dipper's lazy reach. "With that attitude it sounds like anyone would do." Bill snorts and Dipper notices the faint blush building up on his cheeks, "Even me."
"Alright." Dipper says and this time he lets himself smile because Bill's confused expression is too much.
"Alright…?" Bill repeats in confusion.
Dipper decides to lean forward and grab Bill by the arm. He shoves his laptop aside causing it to hit the floor and break as he pins the demon beneath him on his bed. Bill's face is flushed with a blush and he moves his mouth dumbly as he struggles to form words.
"I'm in the mood to have sex with you if you're up for it too." Dipper smirks and brings his face closer to Bill's, only stopping less than an inch away.
"P-Pine Tree—" Bill stutters stupidly.
"You've been watching me masturbate countless times," Dipper says, "Deny it all you want Bill, we both know what's what. So how about we give in a little and have fun?"
Bill's blush deepens and he looks away. His lips tremble and he bites his lower lip in the hopes of stabilising them. Dipper smirks at him. He looks so adorable.
"You're not serious…" Bill mutters, "You're just getting back at me…"
"If I was, I wouldn't drag this out for so long." Dipper says in all seriousness, "My dick's starting to hurt because I still need to cum."
Bill flinches at the comment and looks down at the gap between their bodies. He can see the obvious tent in Dipper's boxers. Bill looks back up, his eyes wide as he looks for hints of sarcasm or jest in Dipper. He finds neither. Dipper is very serious.
Bill looks away again and raises an embarrassed hand to his face, "Okay…" he says very quietly.
Dipper smirks as Bill shifts and waits. He doesn't look in his direction and he's sure the demon's heart is beating insanely fast – provided he does have a heart, of course. As much as Dipper wants to devour Bill and make him shout his name, he isn't about to start so suddenly. For one thing, he's not convinced Bill is really consenting to this and, because Dipper fancies himself a good person, he wants to make sure before they progress – if they progress.
"You don't have to if you don't want to, Bill." Dipper says softly. He hopes the demon'll vanish quickly if he really doesn't want to so he get to ejaculating.
"Don't patronise me, Pine Tree!" Bill hisses, "I'm a demon, not a child!"
"I'm just checking." Dipper chuckles. He leans closer and hovers his mouth barely an inch from the skin of Bill's neck. Bill whimpers and bites his lower lip as Dipper's breath tickles his skin, "If you want to stop at any point, just say so."
Bill opens his mouth to say something snarky but a choked moan escapes instead as Dipper finally presses his lips to the demon's neck. It's a short peck at one area and yet it pulls a lecherous sound from Bill. Dipper moves away and to the area just beneath Bill's jawline. He presses his lips further against the skin and licks testily. Another moan falls from Bill's lips as he tangles his dingers in Dipper's hair.
Dipper grins and works the sensitive area. He mainly licks and sucks on the erogenous flesh but occasionally nibbles at it. Bill is quivering beneath him and trying his best to control the sounds pouring from his mouth. Dipper notices and decides to make it his quest to get Bill to be as loud as he can. He reckons it'll be very fun.
Dipper pulls away from Bill's neck and looks at the mark he left in place. It's pretty dark and Dipper figures it'll last a very long time. He grins at himself which earns him a confused glance from Bill.
"What are you smiling about?" He asks.
"Nothing." Dipper says, "Just happy."
Bill seems to blush all the more at the declaration. He looks away and frowns – Dipper isn't sure why. He moves back to the demon's neck and kisses his way down, only stopping when he reaches the yellow dress shirt. Dipper pops out each button and continues to kiss his way down Bill's chest. He stalls around the nipples. He takes the left one into his mouth and sucks at it briefly. Bill makes a strangled sound of surprise, this being said, he doesn't seem displeased. Dipper thus returns for more. He swirls his tongue around the pink nub and occasionally glides his teeth over, which makes Bill gasp every time. He toys around with the nipple for a bit longer before moving on and Dipper would be lying if he said he wasn't surprised when Bill protested with a very quiet and brief growl.
Dipper gets down to the hem of Bill's pants. There's an evident bulge which reminds him of his own aching cock and the lack of stimulation he has been given. Dipper gets an idea and he hopes Bill will go along with it. He begins by pulling down the demon's pants and freeing his prick from its confines. Bill gasps at the air hitting his erected member and whimpers a little when Dipper begins to touch it. However, before Dipper starts really pleasuring Bill, he shifts their position to the infamous sixty nine. Bill is surprised but says nothing.
"Don't leave me hanging, Bill." Dipper smirks, "Didn't you offer to get me off?"
Bill flinches at the comment. He says nothing and nods, carefully pulling out Dipper's cock with a teasing touch. Dipper groans and shifts a little as he feels Bill's breath against his tip – he wonders if the demon is doing it on purpose or not. Dipper pushes the thought away and refocuses himself on the dick in front of him. He wraps his whole hand around the shaft and feels Bill do the same in turn. He then pumps slowly and groans as the demon continues to follow his example. They keep this up, occasionally varying in intensity until Dipper decides to lick the tip of Bill's cock.
Bill gasps and moans in surprise. The sound is extremely amusing and Dipper decides to do it again. He's rewarded with the same sound and a weaker pump to his dick. Apparently Bill can't concentrate on anything while receiving a blowjob. Dipper grins. He's always gotten off faster with sound over touch and if Bill continues to be deliciously vocal, he'll be fine.
Dipper engulfs the tip of Bill's dick and gently sucks. At this point, Bill gives up entirely on trying to pleasure Dipper. He falls back onto the mattress and covers his mouth with his hands in the hopes of stifling the sounds he's making. Dipper smirks and takes in more of his cock. He does have the personal mission to ruin Bill anyway. He hears another muffled moan and Bill bucks his hips wantonly – perhaps Dipper has already ruined him. Regardless, he bobs his head over the member and Bill's practically screaming in ecstasy. To say it doesn't contribute to Dipper's self-esteem is entirely false.
"P-Pine Tree—" he stutters breathlessly between muffled moans, "Wait—"
This is the one moan Bill doesn't have a chance to stifle and it's the best one. His voice is so erotic and sinful Dipper almost cums himself but, at last, Bill's the only one who finds release. However, Dipper doesn't mind that much. It gives him an excuse to take things further – if Bill wants to, of course. He swallows the cum in his mouth and crawls off the bed to fetch lube and two condoms. He comes back to a breathless and curious Bill who's watching him with glazed eyes.
"What are those for…?" He asks.
"Sex." Dipper says as he gets back onto his bed, "And to limit the mess."
"You humans are so gross…" Bill mutters tiredly and covers his face with his arms.
"So you didn't enjoy that?" Dipper teases and he pops open the bottle of lube to squeeze some on his fingers.
Bill blushes ten shades of red and looks away. He refuses to say anything but the evident twitch of his cock speaks loudly for him. Dipper chuckles and places himself between Bill's legs. This draws the demon's curious gaze again.
"I'm still hard." Dipper states and gestures at his displayed erection with his chin, "You still going to stick with what you said and get me off?"
"…What are we going to do next?" He asks quietly, his breath hitching as Dipper's fingers find their way to his hole. They're cold and slippery from the lube.
"Sex." Dipper says with a lecherous smile. He pushes his first finger in Bill and relishes his moan and his facial expression. Lust is again clogging the demon's eyes and Dipper feels the need to say again: "It's important you know you can back out at any time."
"Damn it, Pine Tree, just shut up!" Bill snaps, "Your whole consent thing is getting really annoying!"
"Alright." Dipper chuckles.
He thrusts his finger in and out of Bill, earning whimpers and mewls until adding a second finger. He detects a bit more pain in Bill's moans but it's normal and it subsides very quickly. He stretches him well for the third finger – the addition of which Bill hardly feels. He's a moaning mess, clutching at the bed covers beneath him and thrusting against Dipper's fingers in the most erotic of manners. Dipper enjoys the sight immensely and he could keep going for a long time but his cock is protesting and hurting and he can't stall any longer. He's pretty sure this is getting unhealthy.
Dipper pulls his fingers out to Bill's mild confusion. He then takes off Bill's pants the rest of the way and casts them aside without a second thought. Dipper breaks the condom out of its seal and stretches it over his cock before doing the same for Bill. Bill moans and bucks at the contact, quickly becoming frustrated when there isn't any more. Dipper doesn't pay him much attention and concentrates more on coating his dick in lube just to make sure there's really enough not to hurt Bill.
When he's ready, Dipper pushes the tip of his cock to Bill's stretched entrance and waits. He teases a bit by resting the tip against it but never going further. Bill whines and moans desperately. His cock is hard again and Dipper would be lying if he said he wasn't impressed with Bill's rebound speed.
"Pine Tree—" Bill whines.
"Beg me for it." Dipper demands with a playful grin. He probably shouldn't be wasting more time but he's already come this far so what's the harm in adding a couple more seconds?
"You're not serious…" Bill says with a frown.
"I am." Dipper grins, "You've already begged me with your body now use your words."
Bill grits his teeth and bites his lip. He looks away when he says: "Please…fuck me."
Dipper pushes his cock further against Bill's entrance but keeps it from breaching. He smiles at Bill's frustrated growl.
"Come on, Pine Tree!" he whines, "What do you want to hear!? I already asked you to fuck me and I was polite about it! Now put your frigging dick inside of me and fuck my brains out, I'm done waiting!"
Dipper supposes this is the best he's going to get. He complies with the demand and pushes his dick in quickly until he bottoms out. Bill isn't fast enough to cover his mouth and the moan that escapes. Rather than start pummelling Bill's tight ass immediately, Dipper reaches for Bill's wrists and pins them on either side of his head. Bill's breath hitches and his pupils dilate.
"I want to hear you, Bill." Dipper says softly.
Bill blushes from ear to ear and nods. Upon receiving his compliance, Dipper pulls nearly almost all the way out and pushes back in. he's not rough with his thrusts yet but he's sure he will be when Bill gets used to everything. Bill moans and glances down between them. He watches intently as Dipper thrusts into him, his cheeks heating up as his moans get louder. He looks up at Dipper who's been watching him and wants to avert his gaze but finds that he can't.
"I want you to say my name." Dipper breathes between groans and thrusts.
Bill nods because the only thing he can do with his mouth is moan at the moment. Dipper decides to increase his speed and strength of his thrusts consequently augmenting the level of Bill's moans. His room thus fills with the sounds of the bed creaking, skin slapping against skin, and Bill's loud moans. The demon desperately tries to meet each of Dipper's thrusts but their position is limiting.
Dipper finally begins to feel the familiar coiling of heat and pleasure in his abdomen. He's going to cum soon but he can't be certain for Bill. He releases one of Bill's wrists in favour of pumping his twitching cock in time with his thrusts. Bill throws his head back and he's practically screaming again. He doesn't seem to be realising that yeses and pleases are mixing themselves in with his moans. Dipper isn't about to tell him though, he's really getting off on the sounds the demon is making.
Suddenly, Bill's moans are far louder than they once were. Dipper soon realises it's because he found the demon's prostate. He continues to pummel into it and relishes the sight of Bill losing utter control. The only word that's spilling from his mouth is now Dipper's name. They cum together with a few more thrusts and pumps. The mess is mostly contained by the helpful condoms. Dipper collapses on Bill. He's utterly spent and has never felt more relaxed in all his life. He waits to catch his breath a bit before pulling out of Bill and discarding the condoms into his room's trash can.
Dipper gets rid of the clothes he's still partially wearing before getting back onto his bed. Bill follows him with his eyes curiously and quietly.
"We're not going at it again, are we?" He asks, "I don't think I can anymore…"
"No, don't worry about it." Dipper laughs, "I just want to go to sleep now."
Bill watches his shift to his left side and tucks his hand beneath his head. Dipper doesn't say anything else and closes his eyes to fall asleep. When he wakes up the next day, his broken laptop is fixed and sitting on a chair. He supposes it's Bill's doing and that he hasn't lost as much power as he thought. Speaking of the demon, he's nowhere to be found. Dipper smirks to himself. He knows he's going to get plenty more visits from the demon and that these ones will be much more forward.