My grandfather used to this trick to me when I was a youngster.
So how do you do it? Do you wedge the coin between two fingers on the backside of the hand? I did a google search, but didn’t find anything.
Obviously the coin was palmed. Try googling “palming a coin” and you’ll find all the common techniques for making a coin appear or disappear in your hands. Just knowing doesn’t help you much. It takes a lot of practice and some misdirection doesn’t hurt.
I just googled for that and got a lot of sales pitches for specialized coins rather than how to palm a coin.
To palm a coin, you can lay it flat on your palm and pinch it between the fatty part at the base of your thumb and pads at the base of your fingers. With some practice you will be able to conceal things there without anybody noticing. With some more practice, you can pull it out with the fingers on the same hand, just like magic.
FYI, I’ve always been told that little kids are difficult to fool w/ magic because they aren’t conditioned to be distracted like adults are. I imagine that’s why the “behind the ear” bit is so important, they can’t watch your hand back there.
I googled and found a bunch of places selling how-tos, except for this one. However when I do this trick, I use a different method:
Holding the coin between my thumb and middle finger of my left hand(I’m a lefty), I grab at it with my right hand (making an alligator mouth with my right hand I place my thumb under the coin).
Then (and this is the part that takes practice to make it look good) drop the coin into your left hand while ‘grabbing’ at it with your right hand.
Now kids think the coin is in your right hand when really it’s in your left hand, make it disappear, by blowing on it, or having them do it, or any number of misdirections and then(since I’m no good at this) I just move my clenched left paw behind their head and touch their ear.
Voila!
Reminds me of the Calvin & Hobbes strip where the trick was immediately followed by Hobbes shaking Calvin upside down looking for more money 
“Anything yet?” “Just a bloody nose…”
I did it once.
It involved a pentangle, live chickens and lots of blood.
Didn’t seem worth the effort.
Also, the coin turned out to be an obsolete NYC subway token.
I’ve done it two ways. First, I’ve put the coin in the center of my palm. Second, I’ve had my fingers curled, and held the coin with my pinky. In both cases, you have to make it look to the person you are doing the trick to like your hand is empty, so in the first case you make sure that your fingers are held out straight and your thumb is out so it doesn’t look like you are holding a coin in your hand. In the second case, I have my index finger and thumb in a kind of “pinching” position, with them spread apart enough that it is obvious to the other person that there is nothing there (and in that position your hand naturally wants to curl the other fingers). With either method, once the hand is behind their field of view you simply flip the coin up in between your thumb and index finger and then pull it back to show the coin that has “appeared” from behind their ear.
The advantage of the second way of doing it is that if there are other kids around they won’t see the coin either. This can be done with the first method as well, but it’s a little harder to do and make your hand look natural.
You can also put the coin between your fingers. The way you do this is you hold your hand flat vertically with your fingers together, palm slightly towards the person’s face, and you have the coin between your fingers sticking out the back side of your hand. You have to take care to keep your hand rotated so that the person can’t see the coin, and if there are other observers around they will see the coin.
I’d do it like flightless says. It doesn’t require any elaborate palming. But, get the left hand moving to the ear before the kid starts searching you.
Another “fun” thing to do is at some point just stash a quarter under a cup (or whatever) across the room.
Now, with another quarter in your left hand, “grab” it with your right. While you make a show of opening up your right hand (say with a “flourish” of the fingers and turning the hand over a), stash the coin with your left (pocket it or drop it between some cushions).
Show your now empty left.
Now tell the kid to pick up the cup.
By the way, while Grandpa used a quarter, you can allow for inflation by using a dollar coin. Suzys and Sackies are just a little bigger than a quarter.
Fooling children with parlour tricks is easy. Even an old codger can do it. Maybe start off slow like stealing their nose. (It’s really just your thumb)
Isn’t this called Busking? I have a friend who used to do magic in bars (Before he got famous). We used to pick up enough for beers and dinner. This was in the old days of course. These days some bars pay the magicican (Just as they employ Pocket pool experts).
WAG Very very carefully.
Simple sleight of hand. Exact technique varies with practictioner. Look for the trick on a ‘magic’ site.
Re: How do you pull a coin out of an ear?
Materials
Coin
Ear
Procedure
- To set up, place the coin inside the ear.
- Bring in your audience.
- Reach into the ear, grab the coin, and pull it out.
and, if you want to make more things more dramatic, you can have the child pretend to throw a coin up in the air and you can “catch” it in a paper bag. Except that of course the child doesn’t have a coin - you have already got it in your other hand. Grab a paper bag, hold it with your empty hand with the thumb on the outside and the rest of your hand inside the bag. When the imaginary coin is thrown up in the air, hold out the bag to catch it. When it should come down, snap your fingers where you are holding the bag. It will look and sound as if the coin landed in the bag. You can then have the kiddo look in the bag, and when he’s doing that, you put your other hand behind his ear, and pull out the coin. heh heh. Nothing makes you feel so smart as tricking a small person into trusting you. Grandfather heaven.