Hey! One advice I'd give you is trying out anal play, its pretty easy to get into dom space when you're in control and its not a full blown sub feeling for him! If there's anything specific he likes doing, try incorporating little dominant touches in it, simply staying in top of him, being verbal, ordering him around or just telling him what he's supposed to do are great ways to incorporate it more!

From there on out you could just express your needs to him and see if there's anything he would be willing to give a shot! At the end of the day no one knows what you like unless he's gibing it a shot!

I hope this helped out a bit and I wish you the best of luck <33