Make him cum 3-4 times in a very short time span, in an effort to make him very sore for a few days.

"Tuck it in" all day while at work, very uncomfortable.

Flog himself until his ass is red. If you have a cam, you can surely inspect it.

Have him fuck something he normally wouldn't in an effort to embaras him. I think I read somewhere a dom mad her sub try some vegaetables around the house, handfull of crushed ice, napkin holder...

shave all his hair and let the stubbies torment him for a few days.

* thinks *