I bought one of these the other day, can you guess what it is?

it's a anal plug used to gape the sphincter open.

A doornob!

No, no, a mouthpiece to a brass instrument!

....

A penis ring?

Looks like a urethral plug.

A top hat for a mouse

A top hat

One of those non-conformist, conformist earplugs that make anyone instantly hideous?