There are these awesome little numbered locks that I use with guys that want a key holder but I live to far away to make that practical. Yes I have used the block of ice with some of my guys but I find these to be a lot more effective and work a lot better at keeping them honest.
This was bent over a hay bale in the barn jeans dropped down and bottom exposed. I bent him over and paddled him good. Then I made him unload all the hay.