you riffle through the cards with the faces of the cards toward the spectators, having them think of one they see? I use it all the time, but have no idea what it's called.
I also learned it as the riffle force. I first learned about it in Dan & Dave's 'Commercial' found here as a 1-on-1.
I know it from Commercial as well, though it is not called the riffle force. The riffle force forces a card from the center of the deck using a break,
Although I'm quite sure that you could cut a playing card in half and put that under the card you want to force... should look a bit cleaner from the side, and stop on the card you are trying to force.
To clarify, both are called the riffle force.
I would call the one asked about in this thread a Riffle Peek Force and the other just the riffle force.
Err, actually, it is. If you see commercial's 1-on-1 description, it tells you that it teaches the riffle force, along with the click (snap) change and some variations of it.
So yes, it is a riffle force.
Although I'm quite sure that you could cut a playing card in half and put that under the card you want to force... should look a bit cleaner from the side, and stop on the card you are trying to force.