Typical British phrase meaning: A women who’s got jizz all over her Titties. The “Wet” means after the guy’s ejaculated and smothered the nip with his now floppy disk. And “Nep” signifies the nipple being erect.
Tom: Ay bruvh keep ya titties still I’m bout dash ma kids all over them, init fam
Katie: Ok bad man ting but you got hurry. I need get school before my mam finds out I’m shaggin 27 year olds again hehe
Tom: Oh, ah, ye.*Ejaculates* I’m liking that Wet nep on you piffting.
Also Tom: *Rolls a fat joint* fuck off school ya horny slut