The act of sticking your penis in the opening of the bottom of a popcorn bucket and surprising your date. This results in a very messy and sticky handjob.

When your dog lays a fat dump of shit and your roomate's dog eats it up like it's a king sized butterfinger.

A finger going up the anus of a male being fellated (gay or straight).

When you slide a finger into someones butt, especially when they're not looking.
2 Main reasons: Makes a good caramel color on the inside and a brown coating on the outside AND the finger slides like its coated in butter
GET IT?

The resultant covered penis of heavily lubricated anal sex, looking much like a finger coated in butter.

when you take butter and put it on your fingers and shove them up a girls vagina.

To lube your finger up with butter and then insert into the rectum of another individual.