School Taste Test

[Kara]

One day a teacher had a taste test with her students. She picked a little
boy to do the first test. She blindfolded him, put a Hershey kiss in his
mouth and asked,

"Do you know what it is?"

"No, I don't," said the little boy.

"Okay, I'll give you a clue. It's the thing your daddy wants from your Mom
before he goes to work."

That's when a little girl at the back of the room yelled,

"Spit it out! It's a piece of ass!!"

[MadMike]

I heard one very similar:

Two brothers go to their grandparents for a visit. For dinner, the grandmother makes deer meat. The younger brother takes a bite, and asks what it is, having never had deer meat before.

The grandmother says, "I'll give you a hint: It's what your mother calls your father sometimes."

The older brother yells, "Spit it out! It's asshole!"