rat up a rhododendron

really fast. So fast, in fact, that you won't believe how fast it happened. Often used to describe the speed at which a male penetrated a sexual orifice and began intercourse.

This term, among others, came into wider use in the 1970's largely through the Australian-originated slang of the Bazza Humphreys character who was then featured in the British Private Eye magazine.

He whipped out the old pocket python and fell upon her like a rat up a rhododendron.