How to ease husband into sub role?

My husband and I tend to have vanilla sex, but when we lean more int BDSM play, I’ve been submissive. I’ve taken an interest in switching lately, but he seems to have 0 interest in subbing. He said he’s willing to try anything once, but this isn’t something that naturally appeals to him.

What are some ways I could ease him into the role without making him feel emasculated? I think that’s what’s holding him back, which is strange because he’s very progressive and not even 100% straight, so I feel like he’s capable of getting in the headspace, he just needs to chill out.

If it’s truly not his thing, that’s fine, but he’d like to give it a shot for me.

Edit: ok I spoke with him directly and his biggest concern is being humiliated, feminized, or emasculated. He enjoys face sitting, being told what to do, and is ok with me generally leading the encounter. I think he feels pressure because he knows I have a thing for femboys, pegging, etc. and he doesn’t have an interest in those sorts of things. Of course it’s disappointing, but it’s not a *requirement* to be happy in my marriage. I am ok with those things remaining a fantasy. Just thought yall might appreciate that context.