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.