Possibly my favourite non- control/force move in card magic. I use it constantly.
The convincers I use are as follows- I turn the move from a gutsy 'attitude' move, into a technical, retention of vision move. This is accomplished by...
-Keeping the finders of the 'rubbing' hand open and spread until the last fraction of a second before it covers the whole card. As the hand fully covers the card, the fingers close and the thumb based mechanics take place as the hand moves away from the deck. The vanish is done.
I also, under real heat, use Greg Wilson's handling for the move- I bend my leg at my knee, and perform the move on my lap. But (thanks Greg!), as I do it, I 'lose my balance' and stumble a little, and so return the card to the top of the deck and prepare to do it all over again. This time it's successful. The reason this works is because you condition the spectator to see the hand take the card, then when it fails the first time, it's not as a result of the 'magic' not working, but because you stumble a little on your feet. You repeat the same thing, but with a better balance, it works.
CL