Preston Onion

An action that involves firmly pressing an onion of any size or variety into a persons anal cavity. The onion, once firmly pressed in, is referred to as a "Preston" Onion.

I gave her a Preston Onion. It smelled terrible but she loved it.

My boyfriend gave me a Preston Onion and it made my farts smell great for 3 days.

One time, at band camp, I gave this one chick a Preston Onion and she shat it out her mouth 15 hours later.