That sort of stuff is what usually happens to people that commit sex crimes. In addition to prison.
This guy isn't having it any harder than anyone else who did something similar.
Or take it one step further...what if instead of an 18 year old male, it was an 18 year old female he did this to...you know...as a joke?
Still too severe?
Honestly, I couldn't care less about this guy or what he got in regards to a sentence. My bigger question is, what kind of a person sees a passed out guy and decides that the best way to embarrass him is to yank our your cock and balls and put them on his mouth? This may just be me, but I'm almost positive that I'd have come up with several dozens things before the idea of pressing my junk against another guys mouth...