放屁

The aunt enters the room to give the little girl a goodnite kiss. Like she always does when she visits the kids.

B2: I gotta put these two toys next to me and kiss them good nite
Aunt: What about a good nite kiss for your yee yee?

(Big smack of a kiss on the yee yee's face)

Aunt: What are the names of your toys?
B2: One is 七仔, the other one is 放屁。
Aunt: 放屁? That's to fart, you know?
B2: Yah, sometimes he farts.

You just cannot argue with logic from a 4 year old.