Great question E,
Some of the things I can think of as I write this which are too extreme for me to try/enjoy include:
- brown showers
- roman showers
- piercing, branding, bleeding
- angry or humiliating scenes
- rough treatment of my testicles (not at ALL a turn-on for me, just makes me nauseated)
- corporal which goes beyond dancing on the boundary between pleasure and pain as a mean to get to subspace. For me, playing on the pain/pleasure boundary is great fun, being hurt is not.
- There are lots of other fetishes which aren't too extreme, but which I just don't have an interest in (some of these things I will do to please my partner if she gets off on them) such as foot worship, elaborate knot tying (no matter how artful looking), rubber, leather, or vinyl past the point of accents, doing housework, being caged, cuckold fantasies, human furniture, smoking fantasies, animal costumes, balloons, and lots more.
Somewhere around my late 40s I decided that I for sure wanted to try anything and everything which appealed to me, or that I was even curious about, and even some things I didn't think I would care for, just so I would have some context to understand all sorts of play, and so I made sure I tried everything I might like before I got too old to actively play. I have found that sexually I basically like being somewhat submissive, and have no real interest in being sexually dominant. I love everything from soft and sensual to fairly hard BDSM (if done skilfully, proper warmup and all that), but that my real sweetspot is mild to moderately intense sensual domination with the right kind of woman.
I'm a happy adventurer, so the challenge was always to find ladies (like you and a few others in here seem to be) who were interested in exploring lots of kinky activities, but who were fun and loving about it. I have experienced corporal to the point of getting into full-fledged subspace on several occasion. It is an intoxicating place to be, but most of the ladies who are really into that don't incorporate sex into the activities. It was interesting, but, I really find that I need sexuality in my play. Most of my play ranges from vanilla (which is certainly quite lovely with no kink at all) to being sensually dominated.
I have definitely found that I like for my partner to be assertive about her pleasure even for a vanilla encounter. I don't see anyone more than once who isn't literate, enthusiastic, and willing to let me please her at least as much as she pleases me. A partner who demurs and says "it's all about you" isn't someone I would see twice.
Pleasing my partner is at least as much fun for me as being pleased. I absolutely love a fun role play with "forced" daty/dato, aggressive kissing by my partner, simple bondage, maybe a blindfold, tease and denial, moderate corporal, nipple clamps, all culminating with CFS in CG position.
Other things I have tried and liked or loved (some to my surprise) include gentle bottom play including strap-ons, floggers (especially nice, soft, leather ones, yum!), minor crossdressing in private (more panties, stockings, silky things, not full outfits). electrosex play (violet wand, TENS unit and attachments).
I'm curious to hear what others think is too far out, and also what their own "sweetspots" are.