Keeping hPDA deck squared

I recently began experimenting with an hPDA setup (Again, damn you, Emory!) and I am using a small binder clip to hold my deck. I have enough cards (almost 50) that the clip is hard to fit on the deck. But whenever I pull it out of my pocket, the cards have slid into a semi-fanned arrangement. This only bothers me because I am worried about cards coming out of the pack and being left in my pants to go in the washer or some such. I like using the clip though because it gives me instant access to my blank capture area on the back. Any suggestions on keeping the deck from wriggling apart?