My T says sex is an essential topic in therapy, that people do want to talk about it but are ashamed to. T and I live in a very conservative society where everything's abstinence based.

T has been great at reassuring me that people tend to be sexual beings (and of course there's varying degrees of asexuality), that it's not morally wrong to masturbate or have premarital sex despite our conservative society and lousy sex ed.

While I haven't talked to T about my interest in BDSM (and might never will), I've talked about some really embarrassing intimacy and pain issues I experience. I've also told her I'm more ashamed talking about wanting sex, and sexual pleasure (as someone assigned female at birth) than my shame around sexual trauma. I'm also ashamed about my sexual orientation and gender identity though I'm working on it.

I'm slightly confused about why you experience much shame over aftercare. To me (should I explore BDSM and experience subspace), it would be something akin to "cuddling after vanilla sex", a way of taking care of everyone involved in the scene.