Definition: Rusty Trombone.

Rusty Trombone (noun)

To get one's anus rimmed whilst recieving a hearty reacharound, thus resembling a trombone player in full chorus.

Phoebe's rendition on my rusty trombone last night was so moving, it bought a tear to my eye.

Also known as the "Dirty Bristow", named so after darts player Eric Bristow, where the "playing the trombone" action is replaced by a similar "throwing a dart" movement.

For a DVD demonstration, check out http://smutbymail.com/catalog/product_info.php?products_id=656 (definitely not safe for work).