What does the fist thing mean?

What does the fist thing mean when Rachel gets her 2 fists together and starts banging them together? I think I may have missed it from an episode in the fourth season(where I missed quite a few episodes).

Matt

It's ross's way of giving someone the finger or saying F*** You

~Act

In article , [email] (XGeNsPiCeBoYx) wrote:

405 "TOW Joey's New Girlfriend"...

ROSS: Oh! (He bangs his fists together.)

RACHEL: What was that?

ROSS: Monica knows.

MONICA: It's this dumb thing that Ross made up 'cause he was trying
        to fool our parents. It's a way of giving the finger, without
        actually having to give it. I remember I cried the night you
        made it up, 'cause it was the first time that I realized that
        I was actually cooler than my older brother.

Tennant