Bones, Season 4

Sweets:
It's quite simple. Whatever Agent Booth says, you respond with whatever word or phrase pops into your head, and vice versa.

[...]

Sweets:
The point of the exercise is not to explain, but to respond. Okay? Children can do this.

Brennan:
Because it's childish.

Sweets:
Can we just try it, please?

[...]

Booth:
Hunger.

Brennan:
Sex.

Booth:
Whoa.

Brennan:
Horse.

Booth:
Cowboy.

Brennan:
Child.

Booth:
Baby.

Brennan:
Booth.

Booth:
What, do you think I'm a baby?

Brennan:
You're a father.

Booth:
Oh. Mother.

Brennan:
Birth.

Booth:
Happy.

Brennan:
Sperm.

Booth:
Sperm, isn't this kind of weird?

Sweets:
No, keep going.

Booth:
Ok. Egg.

Brennan:
I want a baby.

Booth:
Whoa!

Brennan:
Horse.