well honestly you know him best and different people have different reactions to bdsm. If you outirght say "I want to try some kinky things in the bedroom" he might be thinking anything from "she wants to wear leather and use a bullwhip on me?" to "so... she wants me to lightly spank her on the behind?"

people have different ideas of what bdsm is especially if they're not really in the community... I know some people think "OMG! BDSM??? like whips and chains???" and not realize at all that a simple scarf to the headboard and getting tickled with feathers is considered light bondage.

I suggest being SPECIFIC about what you want to try be it blindfolding or complicated rope-work.