Mark stood in the doorway of their bedroom, heart hammering, as his wife Lisa led the bigger man inside. "This is Derek," she said, voice thick with lust. "He's going to fuck me while you watch, and you're going to take it like the cuck you are." Mark's cock twitched in his pants even as shame burned his face. He'd never touched another guy, never even thought about it, but the way Derek's thick bulge strained his jeans made something raw and hungry twist in Mark's gut.
Lisa stripped fast, dropping to her knees to suck Derek's heavy cock. Mark watched every wet slurp, every inch disappearing down her throat. Derek's eyes locked on Mark. "Get your clothes off, cuck. Show me that little dick." Mark obeyed, stripping until he stood naked and hard, precum already leaking. Derek grinned. "Now come here and hold her legs open while I pound her."
Mark climbed onto the bed, hands shaking as he gripped Lisa's thighs. Derek slammed into her, the wet smack of skin on skin filling the room. Lisa moaned loud, eyes on Mark. "Tell him how good it feels," she ordered. Mark's voice cracked. "Fuck her harder. Stretch my wife's pussy." Derek laughed, thrusting deeper, then pulled out and grabbed Mark by the hair.

"Your turn to taste it, first-timer."
Mark's mouth opened before he could think. Derek's cock, slick with Lisa's juices, pushed past his lips. It was hot, thick, the taste salty and forbidden. Mark gagged at first, but Derek held him steady. "Suck it like you mean it, cuck. First gay cock of your life and you're already leaking." Mark's own dick throbbed untouched. He bobbed his head, tongue working the underside, spit running down his chin. Lisa fingered herself beside them, whispering filthy encouragement. "That's it, baby. Suck the man who owns us now."
Derek pulled Mark off, spun him around, and bent him over the bed. "Time to pop that cherry." Mark's hole clenched as cold lube dripped down his crack. Derek's fingers pushed in first, one then two, stretching him open with rough twists. Mark groaned into the sheets, the burn mixing with a shocking pleasure he'd never felt. Lisa crawled in front of him, spreading her legs so he could watch her play with her clit while Derek lined up.
The first push of that fat cockhead against his virgin hole made Mark gasp. Derek didn't wait, driving in slow and relentless until his balls pressed tight against Mark's ass. "Fuck, you're tight," Derek growled. "First time getting fucked and you're taking every inch like a slut." He started thrusting, deep and steady, each stroke hitting something inside Mark that made his cock drip onto the bed. Lisa reached under and stroked him in time. "Come on his dick, cuck. Show him how much you love your first gay fuck."
Mark came hard, ropes of cum splattering the sheets while Derek pounded him through it. Derek followed soon after, flooding Mark's ass with hot pulses. They collapsed together, Derek still buried inside. Lisa kissed Mark's mouth, tasting Derek on his tongue. "Next time," she whispered, "you'll beg for it."
The room smelled of sweat and sex. Mark lay there, ass sore and full, knowing nothing would ever be the same. He'd crossed the line, and the raw hunger for more was already building again.