Please report dangerous drivers to the police - Roadsafe. Report to plod, not just whinge here.

it's an elaborate form of slang...

monster is of course short for monster munch, the most popular flavour of monster munch is pickled onion, pickled onion rhymes with bunion, you get bunions on your feet, feet are usually covered in socks, which sounds a bit like sex.

the cabbie was having sex with the guy.

Funnily enough, I was eating monster munch while monstering my girlfriend last night.