its the top shelf at the oriental massage parlor. after a hearty massage she starts to play with your bung with her tongue. Then you rise up on all fours and she starts playing with your unit like its a trombone. Her face will then look rusty, hence the name. Its one of the common techniques taught in massage school.
Tyler won a couple grand in vegas and all he could think about was spending it at the massage parlor for a rusty trombone.
The act of performing anal cunnilingus while reaching up above the testicles to manually administer quick up and down motions to the penile shaft; resulting in a violent yet pleasant explosion. It is then customary for the female to then give a quick blow into the anus for good luck, the lips blowing into the anus sounds very similar to a trombones sweet melody. This was introduced to the Americas in the late 50's.
While receiving a rusty trombone I lost control of my bowels.