I profusely apologize to anyone who already has given a clear tutorial on this trick; there is not enough time in the world to search through every magic 'ible. If you have made one on this trick, please tell me.
Anyways, this effect is very easy, yet at the same time impromptu and efficient. I like the speed of it and its smoothness.
Here is what it would look like in execution.
Step 1: Step 1: Learn the Shuffle
You first must learn my variation on a certain shuffle I've made to move cards to the bottom.
It is hard to explain, but once you have a hang of it, it becomes easy. First, as in picture 1, you start with your thumb on the top card and the four other fingers under the deck. The other hand holds the cards at a slant. Then, start sliding the top card with your thumb and when it reaches the end of the deck, snap the thumb with the card towards your other four fingers. Then, move the whole deck above the card and let some cards slide onto the single card. Clamp your thumb onto those cards This will become easier the more you do it. Move the deck up and then back down. This is just for show and effect. Move your thumb. Repeat the bold until you run out of cards. Repeat the whole thing, but to keep the card on the bottom, slide both the bottom and top cards and snap them together. Practice until you become good at it. You want the process to take only about 5 seconds.
Step 2: Step 2: Bend Cards.
This may sound bad, but it is essential to the trick. Just give a slight bend like in the picture. Don't do it too much, or the audience will suspect something later on.
Step 3: Step 3: Trick Execution Part 1.
First, shuffle the cards in any way you like as long as you don't screw up the bending we did earlier. Then tell a volunteer to pick any card they wish, remember it, and put it back on the top. Use the shuffle we learned to first force the card on the bottom, then keep it there.
Step 4: Step 4: Trick Execution Part 2
This is where the bend comes in handy. Flip over about 1/4 of the cards on top and put them on top. Keep doing this, as long as the next deck you flip over is a little bigger. Then, when you've done it about four or five times, flip over the bottom card quickly, and flip the whole deck over. Now, split the deck in the lower section and say how some cards go that way. Then split it in the upper section and say how some cards go the other way. Because of the bend, there should be a noticeable break in the deck. Split the deck along that break. Say how some cards go back to back. Then, very nonchalantly, flip over the section of the deck that had the single card face-down. This will cause all cards to be in the correct order except their chosen card. Find some creative way to show that their card is the only on face up.
Step 5: Step 6: Create Your Own Patter.
"Patter" is the term used by magicians to talk about the trick and to get the audience involved. It is usually humorous in unexpected ways. Most magic is 10% execution and 90% good patter. Make the trick very much enjoyable using jokes and stories. Without patter, a trick is pretty much dead. Give each and every trick you learn a unique punch to it. If you need help with it, look up videos of the great modern magicians like Ricky Jay or Rene Lavand. They should be quite inspiring, and will certainly help you.