I seldom teach forging. Mostly I forge on events like school or city festivals, christmas markets and so on. So I see my "customers" only 15 to 30 minutes. To make shure that everything stays safe, I handle the steel and the child works like a striker would do - Whomp - tink - whomp - tink... Except when only light blows are needed like bending the heart open.
p.s.: Tink --- (Usually) the father: "Hit harder!" --- Twank - missed. I tell the child: "Don't strike so hard. You will miss. You are simply to young make heavy blows and hit the steel. Get 12 to 16 years old and you will hit ard and not miss.
Willy