I Need The Punchline

I swear this is true. I dreamt I saw Amy Poehler with a tea bag between her thighs. Then the joke came:

Why does Amy Poehler use a tea bag for a tampon?

In my dream I heard the punchline. It was funny. But when I woke up I forgot it.

Help me! What is the punchline to the joke:

Why does Amy Poehler use a tea bag for a tampon?