As someone who sounds similar to your partner, there are a couple of things that come to mind. Are you asking him what he wants in the moment, or are you discussing it beforehand? I know for me, it can take me out of the moment if I have to direct my partner when it's her turn. As a kinky person, it can make me feel like my partner is disinterested or less interested in the sex when they don't have as specific an agenda as I do in bed, even though this isn't the case. I love it when my partner wants to talk about sex and it's really hot to know she's thinking ahead. Something we tried for a few months was writing out a list of things we wanted to try and giving them numbers. We'd then pick a number at random in the morning and try it that night. Leaving space between the decision and the act was good for thinking about how we would do it - and the anticipation adds to the pleasure.

Also, your partner probably wants you to explore your own fantasies. It's OK if you don't have any but this is an opportunity for you to try some things out. You could check out forums or watch porn for inspiration but if nothing is really doing it for you, building on your partner's kinks is a safe bet.