If you have been called a "sly off" then you have snook off with a friend right after being with another friend.
This was used in Middlesbrough alot back in the day, meaning anyone around the age 17+ were either sneaky shitty friends or had shitty little sly off friends.
karren - " I was with sammy the other day right and she only fucked off with beth from Pallypark."
Fay - "Really?! what a fuckin sly off"
29👍 2👎
Having a cheeky wank without anyone knowing.
Be right back I'm off to sly one off before my wife gets back