an unpleasant or rude person. Especially someone who doesn't realize just how obnoxious they truly are.
See that Brown student over there? The one telling everyone how he spent a semester at Harvard and how number theory is pretty much the best thing ever? He's a low trumpet if I ever saw one.
Sticking your thumb up a females butt while goong down on her. Later, sticking said thumb in her mouth during intercourse. Not quite the Rusty Trombone. Its the Rusty Trumpet
Jeff, was she a good girl or a freak? Bro, all I'm goona say is I gave her a solid Rusty Trumpet and she took it like a champ !
When a canadian sticks a kazoo in his ass after eating a bunch of beans and broccoli and farts through it. Usually done after their hockey team wins a game.