Medical Lesson

When Thomas has a student in his surgery, he teaches them all about their intimate body parts. Dominik is a willing learner, and does whatever doctor Thomas tells him to do. The handsome student makes Thomas horny, and he kisses Dominik. They enjoy the taste of each others tongue, and take each others cocks out. Dominik wants to taste his mentor's cock, and starts to suck on it. A twink patient, Dave arrives, and randy Thomas rims his ass and sucks his cock, pushing medical instruments up his hole. Dave wanks Dominik while they kiss. Whose cock will fill his ass?