1. A clown's penis.
2. A term for a funny looking, or irregularly shaped penis.
3. A person behaving in a ridiculous or dick-headed manner.
4. A tasty cake treat marketed by clowns.
"Did you notice Bobo's clowndong was looking a little obvious at little Bobby's birthday party?"
"Did you see Bob drunk and naked at the office luncheon? Man, he's got quite the clowndong!"
"Damn it Bill! Give me back my money - don't be such a clowndong!"
"Mmm - chocolate clowndongs!"
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.