Rusty trombone
Rusty trombone is a sexual act in which a man stands with his knees and back slightly torqued with feet at least shoulder width apart to expose his anus. A person typically kneels behind the man and performs anilingus - more specifically, by pursing their lips and 'blowing a raspberry' on the anus - whilst reaching up beneath the scrotum or around the body to manually apply rapid back-and-forth motions on the penis, mimicking the techniques of a trombone player.