Do a talking session once where just tell him (order him) to tell you top 3-4 cuckold or any similar fetish scenarios which blows his mind (and load) and really really listen - make notes of overall ideas - they would really help

Actually play out conversation with him on one of the themes you connected with. Take initiative and tell him about a particular situation as if it might happen sometime in the future. Asking him to Reiterate the situation, asking him to say out aloud about him being ok about you being slutty is a major major turn on

Subtle footwear related domination if he is into it is a great start too

Hotel room exposure to a staff

Pizza dare

Buying things for your self, pampering yourself and asking him to pay money in a nonchalant way - like it's what he is supposed to do. And tease him about someone else getting to enjoy what he just paid for

Wear tees without bra and ask him to sit in the car while you get out to buy ciggs or something

Telling him about a guy you developed your last crush on

Telling him about past sex experiences if you had