There is a socially understood baseline for sexual behaviour:
- Oral sex
- Anal sex
- Making out
- Jacking each other off
- Massages
- Showering together
- Some mild fantasy kink, like very playful bondage or some other kind of amusing extras.
Most people will want at least a few more kinky things, and not everybody will enjoy everything on that list. But you're not going to startle anyone with that. You won't be out of line to try any of those things.
The point is, that is a baseline, not a maximum or a minimum. It's just a solid menu of typical activities with a lover. Which means if someone wants to go more or less than that list, they need to speak up.
If you want to go way beyond that list, it becomes your responsibility to figure out if the other guy would even consider it, before he's invested a year in a relationship with you or something.
So if you want to tie someone up with the belt of your housecoat, you can start doing that and just follow his lead if he is into it or not. But if you want to bind him in a vacuum bag restraint suspended from the ceiling with a hose coming out of his mouth to breathe through, then you need to give him warning early on that you are into some heavy kink. Fingering his ass a little bit, great. You want to get punchfucked by a guy up to the elbow? You need to be upfront about that before you begin dating him.
Same thing if a guy has limits where he doesn't want to do stuff on the standard list, he needs to say so.
"Actually I'm not into oral. Or maybe sometimes, but I need to let you know I never want to swallow cum or have it in my mouth, it just grosses me out."
Or, "Yeah I'd love a massage, but you need to know I have this weird thing where I can't stand people touching my feet." or "Yeah, I love anal, but only to bottom."
A lot of it depends on what you're after. If you can handle a hook-up and that's all you're looking for, then there are obvious fetish hook-up sites. But kinky things are also fun in a relationship, and obviously a lot safer with someone you know and trust.
At the start of a good relationship, people have a lot of fascination with each other, and a lot of curiosity to learn more about what turns each other on. So bring it up sooner rather than later if it is something you can't live without. Or be prepared to do without, forever.
My guy and I have both tried sounding, and we think its sexy and intense. But neither of us were sounding freaks or anything, and it was hardly mandatory to our relationship. We didn't even talk about it until we were together for 10 years. If it turned him off, I would not have cared and could have happily lived without. There's lots of common ground.