Ball stomping punishment on a hard board

I and my slave are on holiday together and slave gets out the shower and forgot his towel to cover his cock and balls. i was very unhappy as i do not want to see his cock and balls dangling around, so i kick his balls while he is kneeling on the floor. but it is not enough to punish him.. i place his balls on a hard table and crush his balls hard, wearing high heels. later on, i take off my high heels and stomp his balls with barefeet, pressing his balls with my full weight in a various way. this poor slave moans a lot, but i do not care. there is no mercy for a naughty slave.