pizza back

It's like pizza face, only in reference to the back.
It's totally gross & disgusting; all the damn zits and pustules.

Quick, turn away!!! Dave's coming and he's got a wicked case of pizza back!!!

public hair

A rather unfortunate misspelling of pubic hair; that nasty-ass hair that grows in your crotch.

♬ "I'm not ashamed if my public hair" ♬

sanitary towel

A sanitary towel (aka. a sanitary napkin, a feminine napkin, a menstrual pad)) is an absorbent item worn by women in their underwear when menstruating, bleeding after giving birth, recovering from gynecologic surgery, experiencing a miscarriage or abortion, or in any other situation where it is necessary to absorb a flow of blood from the vagina.

Sanitary towel is a common term to hear in the UK.

Hey, that swimming pool float looks like a giant sanitary towel!

Jesus Christ on a crutch!

Simply means, "O fuck!" or, "O shit!".

Jesus Christ on a crutch! you shouldn't have done that.