What, is just being candid about being single incel shit these days? It doesn't require a sense of entitlement and a hateful bitterness with potential for violence?
I remember a time when even nice guys were only considered incel-adjacent because their bitterness wasn't hateful or violent.
There were a lot of those things. And then I just asked for one, and she was into it, and she got braver and asked for things she wanted to do, and now it's 3 months later and we have tried out a lot of new things. And are both feeling super stupid for not having been confident enough to do this years ago.
Don't be us. You love each other, you trust each other, so just ask your SO. But ensure them that it's perfectly okay if they don't want to do it, don't pressure them. If they say no, at least maybe it gives them a little courage to tell you what they would like to try.
You bring up an interesting point in that the duration of the relationship may affect the reaction to the question. Maybe earlier in the relationship you're still exploring so the sexual expectations haven't solidified as much. On the other hand, maybe in a longer term relationship there's more trust. I'm not sure what the normal is or if it leans either way.
Honestly, even if you (whoever reads this) are fairly confident they'll say no, just ask respectfully. They're your loving, trusting partner, the very worst that can happen is that they'll confirm your hunch and say no, then move on like nothing happened.
It really depends on what it is and your partner. Some people see a request for a threesome or opening the relationship as the end of the relationship.
I personally don't know if I'd continue a relationship with someone who asked if we could do scat stuff or piss play, especially if it was an open relationship.
Some requests could be too close to previous trauma, like consensual non-consent. Some could lead to a loss of respect, like adult babies.
That said, there is the question of whether you'd want to be with someone who would break up with you over your kinks, so I wouldn't say you shouldn't ever bring it up. I just don't think it's realistic to expect that the worst that could happen is getting a "no".