- Generally a term used to describe one's anus (a.k.a arse hole)
- Comes from the word gash - which is a slang word for a vagina
- Back Gash is a term is often used by gay men.
Gay 1: How was last nighe?
Gay 2: Good, but my back gash is really sore! He was HUGE!
'I shouldn't have had that indian food last night, my back gash is killing me'