Mark's eyes widen as he sees the size of the cock that's about to invade his ass. The man, unyielding, spreads Mark's cheeks and spits on his hole, rubbing the saliva in with his thumb. Mark tries to relax as the man's fat head pushes past his tight ring, a wave of pleasure-pain coursing through him. The man grabs Mark's hips, pulling him back onto his cock, driving it deeper with each stroke. Mark's ass stretches to accommodate the thick shaft, his own cock rock hard from the intense sensation. The man's balls slap against Mark's skin as he picks up speed, fucking him harder and faster until they both explode in a sweaty, panting climax.