I find this is one area I'm struggling a bit. I go through the deck out jogging cards while holding a break between the deck and a small stock of cards but when thumbing through the cards, the deck slips off my stock below my break and I need to keep adjusting to hide the fact the stock is separated from the deck.
There are many effects I've read that call for this sort of situation but none that have offered any suggestions for smoothing out the performance. Any tips or advice to keep my stock in place a little smoother?
I first want to confirm that I get what you mean.
If there was a method where you had to keep a pinky break over the bottom four cards of a face down deck and then, spread the deck, is that an example of the problematic scenario you're mentioning?
I'm imagining it in a Vernon Substitute Transfer/Nolap switch kind of situation.
If it's so, then try holding the break with the barest amount of skin of the pinky. That should solve a whole lot of the problem. Next, try letting go of the tension in the left hand (I'm again, assuming your left pinky is holding the break) and spread the cards in small packets and slowly. Don't put too much of pressure with the left thumb to spread the cards.
Of course, you could keep the left hand tensed up, gripping the deck so that while spreading the cards the bottom-most stock doesn't separate out, but our hands get so used to handling cards that even our worst spreads look natural. If your audience suddenly sees your left hand all tight during one spread, then you're projecting a subliminal message that something's happening.
Regardless, great question. It's these tiny details which go unnoticed. Your question, in fact, made me introspective of my own technique with the VST/Nolap Switch!