Spitroast on LetMeJizz
Two men working a single partner from both ends is the whole premise, one cock in the mouth while the other takes her from behind. The draw is the choreography, the way both men set a shared rhythm and the person in the middle gets used at both ends at once. It plays to viewers who like the idea of being outnumbered, the mix of total attention and zero control. Most scenes build to a swap, the men trading positions without breaking pace.
156 spitroast videos here, all HD and all free. New ones go up daily, so check back if you don't find your scene first time around.