A/n: So I wrote my first trans!dave fic with just Karkat, and then my second one had John in it. I figured I'd best explain how to get from point a to point b.
With a little three-way sex along the way.

"So, Karkat, you still have that crush on John?"

You startle when Dave asks that. Your post-coital conversations tend towards the unusual, sure, but rarely this early and never this serious. Your forehead is still slick with sweat, and you still feel echoes of his bulge inside of you. Fuck, his bulge is probably still warm in the drawer, and he suddenly asks about infidelity?

Oh shit, it's one of those nights again, isn't it? Post-orgasm freak outs are the most dangerous. They're not like the normal panic attacks, and even less like the sex-time panic attacks. They bring a quiet kind of self-loathing, the kind that won't be drowned out for days.

You wrap your arms around his middle – neutral territory, nothing to trigger an even worse reaction – and pull him close to you. He's on his back and you're on your side so it's an awkward hug. He rolls so he's looking away, but that just means you can tighten your grip and make him your little spoon.

"Dave, I love you. You know that."

"Yeah, but that's not answering the question."

Evasive maneuver seventeen unsuccessful. "When I say love I mean it, Dave. It's not pity. I know you still check out at the word 'quadrant.' I wouldn't fucking be with you if I didn't get that."

"I know. Just like I know you're actually not that into the quadrant thing either. But chill, this isn't a jealousy thing. I'm not accusing you of shit. It's kind of… the other way around."

"Dave, you didn't."

"No! Hell no. Give me some credit, man. It's just that when all this shit ended and everyone paired off he got left in the dust. The poor guy's lonely, and he's always been kind of special to me. You can say no and nothing'll happen. I don't wanna fuck up what we already have going."

You sigh, "Yes."

"Really?"

"To the still liking him thing. He's attractive but I don't hate him because, like we talked about before, my hate gland is fucked up. I'm not sure about this, though. If we have sex, even if you're there too, I might end up having mating fondness for both of you and it would be messy."

"Actually, that's closer to what I was thinking of."

"I thought you didn't do poly?"

"I don't do people who have other people on the side. This wouldn't be like that. This would be all three of us."

"Is that…" you peer over his shoulder. "Is that a thing you people do?"

He looks up at you. "Sometimes."

"Doesn't John not like men?"

"Nah."

"But he told me-"

"He told you something a long time ago. When just about all he knew of life was white bread, suburbia, and a fairly conservative dad. He didn't learn that there was anything other than straight or gay until he was seventeen."

"So what is he, then?"

"Eh… both and neither. It's kinda complicated. Still not really sure. Then again, the last time we talked about it neither was he."

"Alright, so what are we gonna do?"

"No idea."

"Dave!"

"I really didn't think I'd get this far."

You roll your eyes, "Idiot. What did you expect me to do?"

"A triple summersault followed by a back flip straight into top-blowing city and have a disturbing combination of kittens and cows."

"Is your opinion of me really that shitty?"

"Nah. Just bracing myself because after the last real heart-to-heart we had in bed you burst into tears and I walked around with pink hair for days."

"God, I hate you."

"Love you too, Karkles."

"Ugh. Get your bulge back out of the drawer and choke on it."

"Sure, whatever."

You let go of him and roll away with a huff.

A moment later his hands are around your chest and he's pressing up against you. "I mean it, though. You're the best, Karkat." He kisses your ear softly.

"Shut the fuck up and go to sleep," you say, but there's no bite left in your tone. You caress his hand gently and he puts his face right in the crook of your neck.

You hope this won't be as bad of an idea as it sounds.