Everything about this statement is funny to me:
1) My husband said it.
2) He said it to our 3 year old.
3) His tone was like he was talking to a buddy of his.
4) He was totally serious.
And 5) Our son did it.
The thing is, our little guy has a tendency to, uh, how can I put this without being crude....stick his hand down his pants. We've been trying to find alternatives and my husband came up with this one for the car. We were driving along when he just looked in the rearview mirror and gave his suggestion. And it worked. Genius.