I am rarely ever disgusted with any particular scene in any movie but...

I was waiting for him to cough up the hairball afterward.

Did you ever see Rubin and Ed (1991)?

https://youtu.be/SDvjRijxJT4?t=90

Crispin Glover and Howard Hesseman

I didn't even hear about this scene before I watched it and thought it was a bit disgusting at the time but was surprised it had caused the controversy it had, same with the menstruation scene. If you've watched enough porn or other unpleasant films, maybe it's a matter of how desensitised to it you are I guess.