It is good to issue challenges for him.  Men love goals, and the thrill of unbelievable reward paired with intense risk or consequense. This challenge has merit.

Tell then you are collecting pictures showing the largest spider they have ever seen in the house.  If it ends up too large, go with the largest fly they have ever seen as a follow-up question,

Try this... Give him a gift with several items.  (collar, leash, handcuffs, strap on, whatever...) Ask him to tell you what will happen tonight, given these treats.  See how creative he can be.  Keep prodding him on, "... And then what?" Then take his ideas or use your own, if his ideas are weak.  If nothing else, you will get a good idea of what turns him on.

Inviting a friend?!?  At first, I thought, "never!" But training is a good thing, and the humiliation brought on by inviting a second friend in on this is a new paradigm.  The devotion to you and respect, not knowing what might come next, is unreal.