2. Divine and Danny Mills in Pink Flamingos (1972)
In every second of John Waters' infamous comedy Pink Flamingos good taste is laughed at and degradation reigns. So, really, any scene in the film can be considered nauseating, though, admittedly, also hilarious and trainwreck watchable.
One key moment involving cross-dresser extraordinaire Divine and his/her on-screen son, the wonderfully named Crackers (Danny Mills), takes the Pink Flamingos sexual cake (the overall cake, of course, goes solely to Divine for his/her devouring of steaming hot feces). Coming in a close second to that shitty image is the sequence in which Divine and Crackers, for no logical reason, enter someone else's house, lick and rub everything in sight, and then engage in oral sex to let off the steam acquired from tonguing down staircases and furniture.
Some might call that the "Oedipus complex"; others, however, would opt for "OMG," before vomiting profusely.