>>416079other nonnas warned you about what could go bad - being his kink dispenser, but I think that if you feel good with exploring with him, go for it and don't worry too much just try stuff you find interesting from his suggestions and see how you feel about it
BUT if you don't want to do something, like ball stuff then don't force yourself, but you can try by slapping, squeezing and the like… he would probably tell you if that is too much, use safe word and have fun
and the most important part - think about what YOU want to do for yourself as a domme, never let him be a lazy pathetic sub! guys love to pretend that they have femdom kink and in reality it means they just want to be lazy. Experiment if being dominant is for you and never force yourself if it is not, or if this specific guy is not good enough to be your slave