She (17) is equally certain that the phrase for going on the piss is "We are at a sesh".
Apparently its because I am old (45!) and it has changed, I think its because she has misheard/misunderstood.
She wont accept what you say because "They are all old too!" but I just want some validation for myself :o
PS before anyone says it, she is almost 18, yes she does drink when at her friends parties and I am ok with that.