(That's not me. That from someone's video teaching the DL.)

Or sometimes they'll do a flourishy double where it's held between the corners and rotates around multiple times or swivels out of the deck or something like that. I think they believe they are emphasizing the singularity of the card with these moves, but in my opinion they are just bringing attention to a moment that should have passed by without note. If a spectator is suspicious of how many cards you turned over, then your technique is bad, or you're performing for someone who knows about double lifts, in which case your flourishy doubles aren't fooling anyone.

We often hear when learning sleights that we should do the action as if we were doing it for real. That is to say, when you pretend to take the coin or pretend to pick up the object, it should look like when you really take the coin or really pick up the object. So when you do a double turnover, it should look like when you do a single turnover. But there isn't really such a thing as a "single turnover." I mean it doesn't have an analogue in the real world. Holding a deck and turning the top card face up and placing it back on top of the deck isn't something that's really done outside of magic. (Perhaps there is a card game where this is done, but I can't think of it.)

So that left me with the question: If I wanted to handle cards in the way a non-card-handler would, what should my double turnover look like? Not that I was going to mimic them exactly. I don't want to look clumsy with cards. But just as a starting point, I wondered how a person who hadn't practiced this 10,000 times would naturally turn a card over on the deck.

I decided to find out. And so, in the intervening months and years, whenever I was with someone who wasn't proficient with a deck of cards—and whenever I remembered to do it—I would take a video of them turning the top card face up on top of the deck. I didn't want them to think too much about that action, so I built it into a trick. That way I could take my phone out to record "something I want to try out," and at a certain point during the trick I'd say, "Take the top card, turn it over, and put it back on top." And thus I had a bunch of "real" people doing the action with a single card that we pretend to do with a double.

The video below collects those clips.