Mah Jong

What does 3f mean in the game mah jong?

I’m playing at yahoo games and people keep saying “3f please”. I don’t even know what that means and they won’t tell me. I know how to play mah jong, except for this!! please help!

I have never played mah jong in my life and have no idea what it means. I did find the information at the website below. I read it and I STILL have no idea what it means, but you probably will.

Good luck!

Board Games with Scott 006 – Mah Jong In Depth