Sometimes when a man masturbates very hard and strokes his manunit very quickly his fist will fly off the end of the manunit. Because of this speed his fist will fly up and hit him in the forehead often very hard. Sometimes this will knock the man out making him unconscious.Two things can help this. First you can get a Masturbation Helmet. You wear this to protect your forhead from your fist. Second you can purchase a Manunit Bumper.This attaches around the end of your manunit and will keep your fist from flying off and hitting you. Some folks wear both just to be secure. With modern science there is no need to worry about hurting yourself by "yanking your crank" or "Making your snake wink" Be at peace and enjoy working your tube steak.