For example, what would be inappropriately off topic to post to LessWrong discussion about?
I couldn't find an answer in the FAQ. (Perhaps it'd be worth adding one.) The closest I could find was this:
What is Less Wrong?
Less Wrong is an online community for discussion of rationality. Topics of interest include decision theory, philosophy, self-improvement, cognitive science, psychology, artificial intelligence, game theory, metamathematics, logic, evolutionary psychology, economics, and the far future.
However "rationality" can be interpreted broadly enough that rational discussion of anything would count, and my experience reading LW is compatible with this interpretation being applied by posters. Indeed my experience seems to suggest that practically everything is on topic; political discussion of certain sorts is frowned upon, but not due to being off topic. People often post about things far removed from the topics of interest. And some of these topics are very broad: it seems that a lot of material about self-improvement is acceptable, for instance.
A lot of this is material which is well accepted at LW.
Humor is commonly upvoted. It's possible that you have a different concept than I do, and mean something specific by jokes. There's a certain kind of hostile humor which may be more trouble than it's worth, but if so, we're going to need to be a lot clearer about what it is.
I'm not sure how much explicit talk about sex there's been here (as distinct from, say, talk about orientation or polyamory), but I don't think a discussion of how to improve sexual experiences would be out of place.
I personally wish torture wasn't so casually used in philosophical arguments-- I'm not convinced that detaching from my revulsion against torture would be an improvement in how I relate to the world. However, I don't think this is a point of view I'm likely to convince people about.
We do have a norm against recommending illegal violence, especially against named targets.
We've got a weak norm against politics. I wouldn't mind seeing strong norms of pushing people to say how they have come to their conclusions about the outcomes of various political policies and structures. I suspect a great many opinions have much weaker justifications than their holders believe.
We have a monthly media thread which includes art of many kinds, and this hasn't caused any problems that I can think of. Also, HPMOR is extremely popular at LW.
We're pretty cautious about discussing activities which are illegal in first world countries.
"Anything that goes on in your bathroom"? I believe we've had some discussions of flossing which have not been a problem, and also a mention or two of how often to bathe or whether shampoo is useful, but that isn't what you meant.
I've run across something which I believe is valuable for [bathroom activity redacted], and I've been hesitant to post about it-- I've gotten at least one weird reaction for mentioning it in person, and feel some embarrassment about bringing up the subject. This reminds me that I probably should post about it, but possibly with rot13 so that people have some warning if they'd rather not read it.
In general, you seem to want to avoid subjects which tend to lead to strong visceral reactions. I think you're enough of an outlier on this that you aren't likely to change the culture. I would be interested in any method which would make it possible to have an emotionally filtered LW-- while I think you're an outlier, you're probably also not the only person with your preferences.