Yes this is a full on lemon, just a warning for those not comfortable with smut. :3
A shudder shook through Zim's body when Gaz's tongue ran along his sensitive antennae, her breasts practically against his face as he was pushed further into his couch.
He felt teeth gently nip at his antennae, a small noise of pleasure escaping him as the sharp tips of his claws dug painfully into her hips.
Gaz lowered herself onto his lap, pressing her face into the crook of his neck, her small hands moving around him to run curiously along his PAK, feeling the smooth texture.
Her brown eyes peeked over his shoulder as she stared at the machine attached to his back, her slender fingers drew circles around the pink spots as she remembered the spider-like legs that he so often used, remembered how she would always stare in fascination whenever he used them, remembered the strength of those legs when he used them to pick her up before, remembered how he used them to hold her arms down as he took her roughly…
Gaz felt her face warm at the memory, she nuzzled her red tinted face into his neck as she felt heat begin to pool between her legs, vaguely noticing Zim rubbing her thigh while his other hand toyed with a strand of her hair.
Her eyes hardened in determination as she suddenly pulled back to look Zim in the face.
He quietly watched her, his ruby eyes staring questioningly into hers as she felt her cheeks grow hotter, her hands remained on his PAK, brown eyes glaring determinedly into his, "Zim, you know those metal legs you always use?"
Zim looked even more confused by her sudden question, his antennas lifting up curiously, "yes. What about them?"
"I want you to do me with them." Gaz muttered, her eyes drifting to glare at the couch beside the invader's head, pale cheeks practically glowing.
One of Zim's eyelids lowered as he stared questioningly at her, trying to hear what she said, "huh?"
Gaz growled in irritation, feeling her cheeks warm more, if that was even possible, "I said I want you to fuck me with them!" She glared harder at the couch, fuming, she hadn't meant to shout that loud.
Zim's confused expression quickly contorted into a baffled one, his cheeks turning a dark green, "w-what?"
The embarrassed teen turned her glare onto the petrified Irken, "you heard me." She grumbled, folding her arms across her chest as Zim's wide eyes continued to stare at her.
After a couple minutes of no response, Gaz started to grow impatient, unfolding her arms, she grabbed the front of Zim's uniform to shake him, "well?" She growled.
Suddenly a wide grin broke across the Irken's face, a mischievous look appearing in his ruby eyes, he raised a hand to twirl a lock of violet hair around his finger, "little Gaz is sure?"
Gaz blinked at his expression, her hand loosened its hold on his uniform as her voice came out quieter than she intended, "yeah."
Her brown eyes widened when Zim spun her around on his lap, laying her back against his chest as she sat on his lap, thin arms wrapped tightly around her small frame, hot breath blowing against her ear, "Zim shall satisfy his little Gaz." He purred.
She heard the sound of his PAK opening, letting out two metal legs to wrap around her legs lifting them up and open. One of Zim's hands left her waist to push her skirt up, then moving to press and rub against the spot between her legs, his other hand drifting up to grip her breast through her shirt.
Her head tilted to the side as Zim nuzzled his face against her neck before nipping and licking at the slender neck. Gaz's breathing began to pick up as Zim continued to rub against her clothed heat, he abruptly stopped causing Gaz to grip his sleeve in frustration, using his claws Zim cut the sides of her underwear, tossing it to the side. Gaz made a mental note to kill him later for ruining her underwear.
Out of the corner of her eye she saw the other two metal legs, one of them went to her shirt, Zim removed his hand as the leg cut through her shirt and bra, moving away after it was done as Zim happily brought his hands back to her now exposed chest. Gaz growled lowly, glaring at the Irken from the corner of her eye, he just had to rip her shirt and bra. Zim ignored her, bringing his face up to hers, he licked along her warm cheek, as his hands played with her soft breasts.
Gaz jumped when she suddenly felt cold metal prod at her entrance, looking down she watched as the metal legs ran along her slit, one of them circling around her sensitive bead, causing her to shudder in pleasure. When one pressed against her entrance, she felt hesitation go through her as she wondered if the tips would be dangerous.
Surprisingly Zim seemed to notice her stiffening in hesitation, he brought his mouth to her ear, "do not worry, Zim is able to blunt the sharp tips." He assured her, zipper teeth biting the top of her ear.
Gaz relaxed once she learned that the metal would not be cutting up her insides. She bit her lower lip when one pushed inside her, the other continuing to run along her slit, Zim was nibbling her ear, hands still on her breasts as his fingers pinched and rolled the nubs in his gloved fingers.
Her breathing picked up as the other metal slipped inside her, alongside the other one. From her position she could easily watch as they swiftly moved in and out of her, small hands fisting into Zim's pants as she felt the cool metal scrape softly against her inner walls, causing her back to arch in pleasure.
She felt Zim buck his hips up, clothed erection pushing against her lower back. Blinded by the pleasure rushing through her, Gaz didn't notice when Zim's hands left her breasts to undo his pants.
Gaz felt the metal legs around her legs help Zim lift her up, her dazed brown eyes suddenly widened when she felt Zim's hard member press against her puckered hole, trying to push into her tight hole.
She growled at the discomfort, turning her head to glare at him, "I didn't say you could fuck my ass."
He threw her a cocky smirk, "Zim wants pleasure too," he grunted as he managed to get inside her, "ugh you are almost painfully tight."
Gaz couldn't help the small smirk that pulled across her lips, along with the sarcastic reply, "whiner."
Zim growled at the insult, thrusting his hips up roughly, grinning when Gaz let out a surprised cry. One of his hands stayed on her hip as the other drifted back up to her breast as he began to slowly move within her, the metal legs still steadily pumping into her wet core.
Gaz raised a hand to languidly run along Zim's antennae, trying to focus more on the pleasure the metal was giving her instead of the pain.
A groan escaped Zim as he felt her soft fingers run along his sensitive antennae, he used the hand that was holding her hip to turn her face towards him, shoving his mouth against hers, his long segmented tongue slipping into her mouth to play with hers, hips starting to move faster against hers as he felt her hole stretch to accommodate him.
Gaz moaned loudly as one of the metal legs found a particularly pleasurable spot inside her, Gaz's hips began to move as the leg brushed continuously against that spot, Zim bit her lower lip roughly as she rotated her hips, heat shooting through his body as his hips thrust up against her backside.
Zim separated their lips as his ruby eyes looked over her shoulder, he let out a shaky groan as he took in the sight of the two metal legs furiously working her hot core, he bit her shoulder as his hips started pumping into her faster.
Shaky breaths left Gaz's open mouth, eyes closed in bliss from the mixed feeling of being taken from both ends, the cool metal feeling good inside her hot passage.
She felt heat spread throughout her body when Zim lowered one of his hands to play with her sensitive bead, her head reeling back as a loud moan escaped her, spasming muscles tightening, causing Zim to come after her, groaning out his release.
After coming down from her high, Gaz laid limply against Zim, feeling exhausted as the metal unwrapped from her legs, retracting back into the PAK, the ones inside her slowly slipped out to follow the first two.
When Zim slipped out of her, Gaz twisted her body sideways and gripped the front of the Irken's uniform, her tired eyes glaring at him, "once I get my energy back, you will pay for ruining my clothes."
Zim merely chuckled in reply, he moved them so they were lying down on the couch, he ran his fingers through her hair listening to her breathing slow down as she fell asleep; he made a mental note to do this again.
This was really random, I just wanted to do a smut with those PAK legs, I always thought that they were interesting, and Gaz looks like she would be into that kind of stuff. xD
Thanks for reading! :3