A catch 22 that somehow revolves having sex with a woman.
I got herpes from another woman. If I have sex with my wife now, she'll leave me. If I leave her though, I'll never get to have sex with her again. What a snatch 22!
A woman who is so ugly that you would need to consume such a vast amount of alcohol to render her shaggable, that you would be unable to obtain an erection anyway, thus creating a paradox.
"Shit, that bird's a right munter."
"Yeah, she's a genuine snatch 22!"