I saw this at LIFF last year. It is very, very weird, but entertaining and cute in an Ophelia Learns to Swim kind of way.
Basically, it's about a saving-herself-for-Jesus high school student who discovers she's got a toothed vagina (see Freud) when a man tries to rape her and her fanny bites his cock off in retaliation. Naturally, her reaction to this is to go around seducing bad guys and biting their cocks off. If you've ever wanted to see men screaming in pain and quite clear shots of them with their cocks bitten off, spewing blood from the stump, this is the movie for you.
Goodness, I watched half of this curled up in a foetal position in the cinema willing the male characters to PUT IT BACK IN! SAVE ME THE SIGHT OF ANOTHER DISMEMBERED COCK.
It manages to be a winning combination of very camp and very nasty. Possibly because the actors were playing it very straight while the direction hammed it up B-movie style.
On a side note, if her step-brother really did always do his girlfriend up the bum because of his 'fear of fanny' wouldn't that delightful genital piercing have ripped holes huge holes in her lower colon?