Trashy.

This actually happened to a mate while he was stuck in traffic in Brixton. He assured me he wasn't curb crawling.

Skanky crack addict knocks on his window, " Do you fancy a quickie for fifteen quid?"
He does his best to ignore her.
"Okay, what about a blow job for a fiver."
Desperately willing the traffic to move.
She, becoming more urgent lifts up her t-shirt to entice him, "Alright then I'll let you have a feel of my tits for a quid."
The road clears and he's off like a shot...apparently.

Apologies if I've overstepped the mark at this festive or any time.