All jokes pertaining to sperm, vomit, poo, wee, snot or withered hands are truly otiose - it's impossible to believe even adolescents find this kind of thing funny (although youth always surprises - that is its beauty).
Crucially, the film has a kind of slack, haphazard quality that makes it feel criminally cheap, for all its high production values and pretty heroines. It's like going on a ghost train in some rubbishy Hunstanton fairground - you never thought it was going to be exciting, but you didn't expect it to make that terrible clanking sound.