I think that for punishment you should revoke privileges, not hit people. They'll grow up much more irritable and scarred if they get hit all the time. They'd get sick of it and fight back, only to be restrained again, and they would overall have a sucky life. Although Bisjac may be correct to some degree, ruining one's taste buds and keeping them in a humiliating shower is not good for a 7 year old's brain.
