A severely aged penis.
"Old people don't have sex because old men get rusty trumpet."
The goal of the rusty trumpet is not for the man to orgasm, but for the man to fart.
Woman: What's that?!?!
Man: Well, you slob on my knob like corn on the cob, then use tree fingers to massage my balls, the job aint done until I fart! Wocka Wocka!
Aaron: We started our own brass band!
Dave: She gave you a Rusty Tombone?!?
Aaron: And then I gave her the Rusty Trumpet!
Aaron: And then we each drank a bottle of Listerine so as to not get E-Coli.
2:A trumpet that has been exposed to too much salty water. Probably the salt included with semen.
"My trumpet is getting rather rusty. Tug over this this 2 ohm resistor instead. "Oh! 2 ohms! FASTER! Ohhh..."