Question about the Svengali

Hey everyone. I'm having a problem with my Svengali deck: sometimes when I do a Riffle Shuffle, a card slips out, and two short cards end up together. (This can happen repeatedly if I shuffle more than once and don't notice the cards have gotten out of order.) My question is: is there any technique to subtly re-set the deck in front of the spectators without them noticing?

Thanks in advance!