doin your mum Share definition Flag An alternate way to say "having sex with your mum". Often used to get someone to fuck off, or as a comedic response to "wyd" "Dude, what the fuck were you doing last night?" "I was doin your mum, doin doin your mum" doin your mum by Neowo September 20, 2019 0 0 Get merch Get the doin your mum mug. Buy Now — $32.95 See more merch