Getting freaky with the boyfriend

Soooo my boyfriend and I are sexually active and we have really great sex. But it’s just your typical missionary, cowgirl, doggy, and oral sex. I have fantasies of getting a little more creative like using handcuffs or blindfolds or even just him being more aggressive. I have NO idea how to tell him I want this. I’ve mentioned it lightly and it kind of just turns into a joke and never happens. He’s my bestfriend and I tell him everything but this seems to be so hard to talk about for me. HELP.