twatflap
The outer labia of the ladybits. Also a good insult for someone who is utterly useless.
"look at the state of you ya twatflap!"
twatflaps
The kebab-meat flaps of the female hairy axe-wound. Can be used in the singular sense as an insult.
Cor! Look at her twatflaps! You could park a bleedin' Lada Estate in those you could!
Oi, Paul - you're a fuckin' twatflap mate!
Oi, Paul - you're a fuckin' twatflap mate!