What you need:
Small or large person
Stand about 6 inches from the wall and push the backside of your hand against it...
Push as hard as you can, using your arm muscles for at least 30 seconds, longer if possible!
Which sounds easy but actually, it's not...
When the time is up relax you arm and put it back by your side, it will lift itself, just like magic. To make this more impressive you can utter a spell and demand that the arm rises!