I found this in “Card Zones – The Immaculate Card Magic of Peter Duffie.” This book describes a stack for four hands and then gives the formula for other number of hands. Since I always demonstrate a five handed stack here are the steps.
This stack requires a crimped card that can be cut to the bottom. For this I use a breather crimp, with the work being put on the back of the card. I start letting the spectator shuffle the deck and then I cut the crimped card to the bottom.
Spread the deck and pull out the four aces as you come to them. After removing the aces and throwing them out to the table, turn the deck face down and casually overhand shuffle, running four cards below the crimped card so that after the shuffle the card is fifth from the bottom.
The next step is to get a break under the twelve card from the top of the deck. I spread the cards in groups of four as I talk about stacking the deck. I take the break as I square up the cards.
Have the spectator pick up the aces and place them face down on top of the deck you are holding. Push over the top two cards (aces) and show them. As the right hand returns them take a break under them with your right thumb. You are holding two breaks, one with the left little finger and one with the right thumb.
With the left hand undercut the deck at the little finger break and place the lower cards on top while you keep the right thumb break.
Now turn the deck into an overhand shuffle position. As the deck turns, keep the thumb break and lift those cards with the right hand in preparation to begin an overhand shuffle.
Situation check: Your right hand holds a block of 14 cards, the top two are aces. The left hand portion has two aces on bottom.
Run one card and throw the right hand block on top.
Run five, milk one card from the top and bottom, and run three. Throw the rest on top.
The stack is now on the top and bottom of the deck. Cut about 10 cards from the top to the bottom (at least 10.) Place the deck on the table and then cut at the crimped card and complete the cut. The crimped card should be on the bottom.
Deal out five poker hands. The fifth hand will have the aces.