Cows in Ears

Have I shared this one yet?

I have no idea of the context. We were waiting in the car while Doug quickly ran into Wal-Mart for something. The kids had been playing, and this is what I overheard:

Olivia: Asleep people can’t plug their ears.

Angela: Unless they put cows in their ears.

Olivia: Yes, you do that.

I have no idea. I honestly have no idea.