"I'm going to kill you."

"No you won't."

This is what we always say afterward. Sometimes we whisper it softly to each other, and we almost feel like lovers murmuring sweet nothings to each other. Sometimes, while we're laying quietly with each other, he'll bolt straight up and yell, "I'm going to KILL you, Dib-stink!" menacingly. I just hook my arm around his slender waist and pull him back down, humming softly.

"No, you won't."

Not after all this time and all we've been through, he wouldn't. My squishy, cute alien. He'd never hurt me, not anymore.

Zim still puts on the airs of an Irken invader, ranting and raving about his schemes to destroy the Earth, but at best, it's a half-hearted facsimile of his former dogma. It's rare for him to report to the Tallest these days, and even when he does, he doesn't have much to tell them. He's taught me a lot about the Irkens, as well; I mean, who am I going to tell? It's not like I still want to get rid of him anyhow.

It's all just a game now.

This- thing we do started about a year ago. I was turning 19. Now that I think about it, I'm stunned that I made it through most of puberty without overtly coming on to him. I dreamed about it, I had fantasies, but I didn't think much of it. I mean, come on, its normal, right?

But, then again, being normal has never been a big concern for me.

Zim never seemed to notice any changes in me, until one day he had to crane his neck to look me in the eyes. After that, he seemed to just shoot up, as if in response, as if he was trying to prevent me from gaining any sort of superiority over him. The first time he ever saw a piercing- now THAT was comical. I had made my way into Zim's base, as per usual, this time fifteen years of age. My eyebrow was still stinging from the recently added metal bar, which I had been able to acquire by lying about my age. At the time, I thought it was the coolest thing in the world. Kids, am I right?

I was up in the rafters of Zim's living room, watching Gir watch that really weird monkey show. I could tell Zim wasn't in here, so I went into the kitchen so that I could go into his underground lab.

As it happens, I reached the entrance just as he came up from it. By this time, he was quite a bit shorter than me- standing normally, his head reached my chest, and his antennae reached up all the way to my hairline.

He always wore the same thing; a long sleeved shirt that looked like a second skin, black pants, elbow length gloves, and of course, his PAK.

As soon as Zim saw me, his eyes narrowed and his antennae flattened against his head.

"Dib-filth, why're you here! Gir! Why'd you let him infiltrate our base so easily-" Suddenly, he stopped, his eyes fixating on the small metal obstruction above my right eye. "Dib! What happened?"

"Huhph-?" I grunted as suddenly, the alien flung himself at me and pinned me to the floor. My head snapped back sharply and collided with the tile, and stars danced in front of my eyes. I was pulled up by the hair, and saw a glint of metal in the hand not occupied with holding me still.

"Holy shit! Are those pliers?"

Jerking my head to the side, his missed with the first lunge. "Stop struggling! I'll get it out for you!"

"Stop it, Zim! I put it there!"

This made him pause, and loosen his death grip on my head. I took the opportunity to roll away from him. Panting a little, I stood up and backed away.

"Why would the Dib-beast put metal in his face?" He squinted at me. "HAVE YOU THE BRAIN WORMS?"

"No!" To this day, I ask myself what brain worms are. "Its just a piercing, okay?"

Zim was flustered. What was going on in that big head? He seemed to actually have some concern for my well-being. Startled by this revelation, I fumbled my way out of the situation.

"I'm going to leave now, Zim. I'll see you at school."

What a misfire that was, but now, I look back on it and laugh. Sometimes, I think its kinda cute, how he was worried.

The first time I made a pass at him was when I was 18, and it wasn't intended. I'm not going to explain it in detail, but this happened and that happened and suddenly, Zim and I were intertwined. His ridged, foreign tongue was in my mouth, and it was...weird, but I enjoyed it more than I'd like to admit. Later, I found out that even just kissing was new to Zim, because it simply wasn't something Irkens did. Instead, Irkens would curl their antennae around each other's to show affection. But Irken culture frowns upon emotional relationships, as it's mainly a military force. The goal is to take over the galaxy and those beyond it by any means necessary, not to have families.

Nonetheless, that was the beginning of our relationship; that sounds right. From now on, I'm going to call it that. Now, the first time we were intimate...

It was actually quite embarrassing the first time. It was the night of my nineteenth birthday. By then, we'd "been together" for about a year; not really dating, but we kissed sometimes, fumbled with feelings for each other sometimes, and it was getting relatively serious. As serious as you can get with someone like Zim.

For my birthday, Zim repaired my glasses, which he had intentionally broken just so he could have them fixed. He considered this a really thoughtful present. I would have felt the same way, but I had to go an entire day without being able to see just so he could be satisfied.

We were at Zim's base, and he was sitting close to me on his couch. He had powered down Gir for the night.

Nothing was being said, and I was really nervous. I'd never even kissed anyone before Zim. I didn't know how to even begin this type of thing!

"Dib-thing, Zim is going to get something from the kitchen." Zim mumbled, standing from the couch. I nodded quietly.

Something I noticed about myself lately, is that I really enjoyed watching Zim walk. He twitched his slender hips occasionally when he walked, and never let his head hang. Usually he kept his chest puffed out and his antennae perked up, almost as if he was constantly standing at attention.

But, to be completely honest, I just liked to watch his ass.

Zim returned presently, holding something behind his back.

He sat down facing me on the couch, and produced a small, red cupcake. It had a little 'D' written on it vanilla icing.

I smiled. A real, genuine smile. Zim doesn't smile all that often, unless you count his maniacal grins, but he started to crack one as well when I took the cupcake from him.

"Do you want to share it?" I inquired, licking a bit of the icing off the top. It was sweet and let it rest on the tip of my tongue a moment before swallowing it. He thought for a moment before declining, and I remembered- of course- that Zim can't eat human food.

The cupcake was really good, and I finished it in about three minutes, Zim staring at me all the while, deducing my reactions.

"Do you like it?"

"Yeah, it was really good."

"ZIM made it HIMSELF!" He proclaimed, grinning proudly. I giggled a little, making a weird snorting sound, and started a little in embarassment.

Just as I was giving up on the idea of getting laid tonight, Zim began to lean in for a kiss, his eyes closed. I panicked for a second, like I always do, then relaxed as his lips softly pressed against mine. Zim scooted closer and shyly curled one of his hands into my hair. I slid my hand up his back and grasped the nape of his neck, feeling his lips part slightly and the tip of his tongue slide across my lower lip.

I shivered slightly, the tingly feeling of goosebumps raising on my skin spreading. I tipped his head back and pushed his lips open, slipping my tongue inside. Zim made a soft noise, opening wider for me.

He moved closer, eventually just sitting on my lap. He moved down to my neck, sucking, pulling blood to the surface, marking me. He does it a lot, possessively. Everything he does - with his lips, with his tongue, with his body - is so sensual, and it can be overwhelming.

Silently, I close my eyes and tilt my head back, exposing my neck and giving him better access. Its a sign of submission and I know he loves it, purring now, nipping me gently at first, then harder.

Zim moved back up to my lips and began to slip his hands up my shirt. I grabbed the back of his head and thrust my tongue into his mouth, my courage spiking. He always tastes like sugar; it's an addictive flavor that I can't get enough of.

"D-Dib-beast- ahh..." he gasped when I began to lightly nibble his earlobe. He restlessly tugged at my shirt, and I lifted my arms so he could slide it off.

I can't remember if we'd ever gotten this far before. He usually breaks it off first, or we're interrupted. But he didn't look anywhere near close to being done, and Gir was powered down...

I laid down back against the couch with Zim still sitting on my lap, this time working on getting his top off. I've never seem him even partially naked before, and every time I tried to put my hands under his clothes he would shy away from my touch.

Needless to say, I was very, very excited.

His stomach was the same soft, pale green as the rest of his body; he lacked a belly button and nipples. I noted this in the back of my mind. I'd have to remember to document it later.

"Don't just stare, Dib-human," Zim said indignantly, leaning down to kiss me once, twice, three times. It turned into something deeper, and he let his prehensile tongue sink deeply into my mouth.

I'm usually not one to test my luck, but I didn't want to just kiss. I wanted more; I wanted all of him.

Gingerly, I reached up to slide my finger down the length of one of his antennae. He froze and shuddered softly. I sat up and he slid down my chest, sighing and cooing contently when I continued to rub his feeler. It was rubbery in texture. I took the tip of it into my mouth, sucking gently; it made Zim's hips buck.

I kept stimulating his apparent pleasure receptor, and began to wonder if Zim even had gentalia. Slowly, I reached down and rubbed my hand over his- well, where it WOULD be. He made a noise of appreciation and began moving his hips against my palm. There wasn't a bulge...Could Zim...Could he perhaps have...?

No, I'm pretty sure Zim's a guy; I mean, he always refers to himself as he..but he's Irken! A completely different species. I had began to panic. I didn't know what I'd do if he had a vagina, or a completely different kind of genitals altogether.

I laid back down on the couch, pulled Zim on my lap, and began to pull off his pants. His eyes were clouded and he looked a bit dazed. He let me get his pants off, and now I was just confused.

At the join of his thin, long legs, was something sort of similar to a woman's anatomy, I suppose. It was a thin patch of skin that was a violet color; it deeply contrasted from the rest of his skin. I rubbed my fingers against it curiously, expecting it to part easily, but it remained closed, the skin only giving slightly less resistance than the rest of his body. Zim gasped and then attempted to hold back a moan; he failed. He leaned forward and gripped my shoulders tight, moving his hips is frantic jerks and twitches.

Fascinated to no end, I pressed a bit harder on the skin, getting an alarmed noise from the submissive Irken. I wrapped my other arm around his back and rolled him onto his back. Suddenly, to both Zim and my surprise, when I reached back down to rub him, there was something there.

Well...it wasn't exactly a penis. It was a lighter color than his skin, but besides that it looked basically like a human males genitalia. I ran my hand down the length of it and Zim arched, sighing, and then I discovered a small hole below it. I assumed that it worked like a human males...'entrance'. Rubbing him with one hand, I wet my fingers with my saliva and gently pushed then against his tiny hole. He gasped and shifted, trying to wiggle away from the foreign feeling. I grasped his hips and pulled him back towards me.

"Agnn...D-Dib...what are you trying to do to Zim?" he demanded breathlessly. Hearing him struggle with my name gave me an unexpected surge of pleasure.

"Don't worry. It'll feel good in a second...I think." Well, what the hell did I know? I had no idea if he had a prostate or anything like that. Maybe he should just top me. It'd be simpler. But he didn't seem to be in any kind of mood to top...

I sat back on my heels. He pulled himself up and looked at me, just like, what the fuck are you doing.

"Um, Zim...You wouldn't know how humans do this, would you?" I asked sheepishly,

Zim narrowed his eyes. "Of course Zim does. Zim knows everything!" he said arrogantly, but there a slight pink hue on his cheeks. "Can we just get on with it?"

"Ah..okay, but-" I was taken off guard by the demand, and he suddenly pushed me down onto my back. In one movement, he yanked off my pants and boxers, exposing me fully. I yelped and tried to cover myself, but again, catching me off guard, he extended his metal PAK legs and restrained my arms.

"We are...definitely different..." he muttered. stroking my member teasingly. I whimpered, pleasant little shocks running through me at the feeling of his latex glove on me. The spidery, metallic limbs of the PAK spread my legs, and Zim looked down at me for a moment, thoughtfully, before flipping me over completely. He grabbed my hair, pressing my face down, and jerked up my hips so my ass was in the air.

This was NOT how I expected this to happen, but I can't lie; I wanted it. I wanted Zim.

He began to press the tip of his finger against my opening. "Ahn- wait, Zim, I have some lubricant-" I was cut off when he, without warning, shoved two completely dry fingers inside. I stifled a small cry of pain, biting my lip until it came close to bleeding. He started moving them in and out quickly and I shut my eyes tightly, trying to take it. Zim began to brush against my prostate and a dizzying wave a pleasure shocked through me.

He, of course, noticed, and smirked. "Say you want Zim." He demanded.

"Ahhh- Z-Zim, I want you- ah!" I cried, as he rubbed that spot quickly. I was seeing stars and was so, so close when he pulled his fingers out. I protested loudly.

"Are you ready for Zim?" He asked. I turned my head to look over my shoulder. He was still grinning, pleased with his dominate position over me. He was stroking himself leisurely.

"W-wait, Zim, please..." I said quietly. A look of concern briefly washed over his features. "You need to use- ah, lubricant, or you'll really hurt me..its in the back pocket of my jeans."

He retrieved it from my jeans and poured a bit on his fingers, staring at it and contemplating it texture. I just stopped him from trying to taste it.

"No, Zim, you put it on your...your thing and then some on me, so it goes in easier."

"I know that," he snapped.

I sank down into my position again, knowing he didn't, as he put some on himself and then some on me.

Shutting my eyes tightly, I felt him line up with my opening. I braced myself, expecting nothing but pain to follow.

It wasn't slow. I don't know if Zim knows the meaning of the word. He simply thrust all the way in, and this time, I couldn't hold it back.

I made a loud, muffled yell that startled him. He was nice enough to wait a few seconds to let me get accustomed to his size before he pulled himself out to the tip. He wasted no time slamming back in, all the way to the hilt.

I cried out when I felt it slide past my prostate. He grabbed my hips again and without missing a beat, began to pound me at a bruising pace, grunting softly. He maneuvered me so I was at an angle where he stabbed my prostate every time he would. My thighs began to tremble with the force of my building orgasm, and my throat became hoarse from shouting, but I kept pushing back against him and begging for more.

Zim was purring in satisfaction above me, occasionally speaking in his native language, a series of chirps and clicks.

"Ah! Zim! Harder!" I managed to choke out, and I felt sweat dripping down my face, but I didn't care. The only thing that mattered was Zim.

He reached down and gripped a fistful of my hair, jerking my head back. I simply moaned at the roughness, so close, almost, my whole body just a bundle of nerves, trembling and quaking. I felt wetness running down my thighs and then I came harder than I ever have before, feeling tears dripping down my face at the force of it, moaning Zim's name over and over as I rode it out.

Hearing my release and feeling me grip him tightly, again and again, prompted his orgasm. He thrust as deeply as possible and let go, and I sighed as his warmth spread deep inside me...

A/N

Hi! Tokumei no Chosha present. This is my first story I've ever uploaded! And it wouldn't be here at all without my amazing editor.

Please leave a review if you liked it/have critique

Also, I would really like to know if I should continue this story or start a new one.

DISCLAIMER: I DO NOT OWN INVADER ZIM OR ANY OF THE CHARACTERS IN THIS FANFIC. ALL RIGHTS GO TO JHONEN VASQUEZ AND THE CREATORS OF THE SHOW AND THE CHARACTERS.