oh a really really good one is having him save some of his seman, or spilling it just prior to a luncheaon or meal with friends present,, have him go to the bathroom or somthing collect his own sperm then apply it to his sandwich , no one present but you and him needs to know that his own personal mayonaise is being used on his food instead of the stuff from the jar in the fridge
its a great way to embaress him with lil to know risk of public humiliation,,its one ive personally had to do cept the seed was my owners etc weg