Gross, fun and with boobies. Piranha 3DD delivers everything he promises: piranhas and 3DD boobs. Story is mostly nonexistent, some situations can be predicted (like the… spoilers… piranha on dick), but at the end I am not sure if this is more a horror or a comic movie. Horror probably because of the amount of red paint, comic because of the amount of stupid situations they can create with piranhas. And David Hasselhoff playing of himself is kind of funny too (but probably too many scenes with him).
At the end, I voted 6 in 10, mostly because of the story. It could get a little better with little effort.