50ps are easy but hard to explain... you hide it on the back of your hand by gripping it with the back of two of your fingers. As you put your hand next to thier ear you make a fist and slide the coin round into your palm using your thumb. That's about as clear as I can make it without showing you (which obviously isn't really practical.) As far as the humbug is concerned... the same thing possibly, only you'd have to do it faster because it would show throughonto the fornt of your hand. Ah, unless it was still in the wrapper in which case you could grasp the wrapper with your fingers, and all would be concealed. Alternatively find some way of genuinely secreting it in their ear until the trick is required. Two quick notes... in the future, children will expect either a five pound note or possibly 20 Euros. Also I'm not sure being straight is a prerequisite for uncleship. But normally is for grandfatherhood.