Written in response to a prompt at the psychkinkmeme over on LJ that said "I want a smexy Shassie-esque fuck or die scenario. Lassiter has to fuck Shawn while a bad guy watches from an unseen location. Lassie's bugged and not allowed to tell Shawn what's going on."

Shawn glanced around the deserted alley uncomfortably. Lassiter hadn't said why he needed to meet Shawn here, but he'd been adamant, downright commanding, about it. Normally he wouldn't mind Lassie trying to play the Big Bad Cop card-it was pretty hot-but right now the other man just seemed jumpy and on edge and the way he was slowly stalking toward Shawn with a strange, determined look on his face didn't exactly do much to reassure him.

"Everything okay there, Lassiface? You're looking kind of intense and snarly. Or more intense and snarly than usual, if you want to get technical about it. Not that intense and snarly's a bad look on you, it's just not something I'm always 100% percent okay with having right in my face when we're alone in a dark, secluded alley together, and did I mention that Gus is expecting me? Because he is, and I'd hate for him to think that I'd ever miss our weekly jerked chicken and Billy Zane night, because that's been an honored tradition for nearly a week now." Shawn's eyes widened and he swallowed audibly as Lassiter took another step toward him. The brick wall against his back felt damp and rough through the thin fabric of his t-shirt, but he barely noticed the sharp scrape of it because every nerve ending in his body was currently focused on the heat radiating off of Lassiter's body.

Lassiter braced his hands on either side of Shawn's head and leaned in until the warmth of his breath just barely washed over the shell of Shawn's ear. "Spencer," he growled. Shawn swallowed again and focused on not going weak-kneed like a teenage girl.

"Uh huh?" Shawn pressed back harder against the wall, because otherwise there was a very real chance that he was going to grab Lassiter and do something unspeakably naughty, and wouldn't that be embarrassing?

"For once in your life, shut the fuck up." Lassiter turned his head a fraction of an inch and inhaled and...wait. Did Lassie just smell him? A shiver went down Shawn's spine, straight to his cock, and when he nodded he could feel Lassie's lips ghost over his cheek.

"Yeah, okay, no problem. I can do that. I have absolutely no problem whatsoever with shutting up. Quiet is my middle name. Why, when I was younger-" Shawn trailed off into a whimper-he'd be mortified about that later-when one of Lassiter's hands slipped down to cup his neck, his thumb tracing a light, teasing line down the front of his throat. Lassie dipped his head and nuzzled at Spencer's jawline, then bit him, and Spencer gasped and scrambled at the lapels of his suit jacket.

"Seriously, Spencer," Lassiter rasped against his skin. "Shut. Up."

Shawn bit down on his lower lip and nodded. Lassie's mouth was rough, biting and sucking hard-and Shawn shouldn't be half hard just from the idea that Lassie was marking him-but his fingers were impossibly gentle as they traced the barest suggestions of patterns across his neck. His body arched up against Lassiter's when the hand that wasn't on his neck suddenly made a surprise appearance at his belt buckle, and his abdominal muscles trembled when Lassie's knuckles brushed his stomach as he deftly unbuckled the belt and undid Shawn's pants.

Shawn seriously thought about saying something at that, because this sort of thing had never happened before in all the times Lassie had shoved him up against a wall and alarms were blaring in the back of his mind, but then Lassie's long, glorious fingers were sliding inside his pants and cupping his erection through his boxers and did it really matter why it was happening so long as it kept happening? Shawn thrust up and let out a high, keening noise at the rough drag of cotton and the warm weight of Lassiter's hand.

Lassie made a tsking sound and murmured 'So impatient' before sucking on Shawn's earlobe and pushing his boxers down. Shawn's knees did give a bit then and his eyes rolled back when Lassie squeezed and ran his thumb over his slit. Shawn was vaguely aware that he should probably be doing something more than just wrinkle Lassie's clothes and make embarrassing noises. He swallowed back a moan and focused on unclutching his fingers, the cheap fabric crinkly and slippery between them, so that he could undo Lassie's pants. Lassie froze against him when Shawn made short work of his belt, button, and zipper and eagerly stroked his hard cock. He made a choked noise deep in his throat and pulled back enough to take Shawn's mouth with his own.

The ferocity of the kiss knocked Shawn's head back against the wall and he winced, but then Lassie was biting his lip and sucking his tongue and doing some wonderful swirly thing that made Shawn grind hard against Lassie's palm and completely not care about something as trivial as a possible concussion. Lassiter ran his hand over the head of Shawn's cock, slicking his fingers with his precome, before stroking down his length again. His tongue was fucking Shawn's mouth and it was so distracting and good that Shawn barely noticed what Lassie was doing until suddenly Lassie's ridiculously, amazingly long fingers were wrapped around both their cocks and he lost himself in the wet heat of Lassie's mouth and the delicious slide of Lassie's skin against his own.

The hand on his neck slid up into his hair, yanking his head back and revealing just that much more of his neck to Lassiter. "Now," Lassie growled as he nipped at Shawn's Adam's apple. "Now you can talk."

Shawn tried, honest he did, but the best he could manage was a broken litany of 'fuck' 'more' 'Lassie' 'please' 'shit' 'God' 'harder' 'more'. Lassie's fingers dug into his scalp, his blunt nails scraping almost painfully, and he bit down on his shoulder so hard that Shawn wasn't entirely certain if the spreading moisture was from Lassiter's mouth or Shawn's blood. Of course, at that moment he didn't particularly care, because Lassie twisted his wrist and Shawn was spinning apart and seeing stars and coming so hard that the world fell out from under him and the only thing keeping him from falling over was Lassie's long, hard body pinning him to that damned wall.

Lassiter shuddered against him, his hips jerking harshly against Shawn's, and pressed his face into the crook of Shawn's neck, gasping out something that sounded suspiciously like 'I'm sorry' as he came. They stood there clinging to each other for several seconds, the alley silent except for the sound of their rough, uneven breathing, before Lassiter's cell phone buzzed in his pocket. It was on silent, but it still seemed unnaturally loud to Shawn's ears. At the first, startling vibration, Lassiter lurched away from Shawn, his eyes cutting to the side, and answered the phone with a short 'Lassiter'.

He was quiet for a long moment, then glanced up at a bordering building, nodded once, and hung up. The tension that had kept him rigid since he'd met up with Shawn in the alley seeped out of his body and he exhaled slowly, his expression at once guilty and relieved. His eyes darted toward Shawn once, his face unreadable, then without another word or look to him, he straightened his clothes and smoothed his hair back into place.

Shawn slumped against the wall, his pants still undone and his shirt already sticking uncomfortably to his stomach, and watched Lassiter's back as he walked away. An aching, hollow weight settled in his chest as he wondered what the fuck just happened.

This is my first ever attempt at anything more sexual than kissing and so-vague-it's-barely-there petting, so I apologize if it sucks. Feedback is always appreciated.

Huge thanks to topetine over on LJ, who not only harassed me convinced me to write this, but also held my hand while I flailed wildly and threw self doubting pity parties in her inbox.

There will eventually be a second part, just as soon as I get around to writing it.