Since December 2017, we’ve had a close reason that certain questions should be discussed only in private. Does this mean that we should, for instance, go through the sexuality tag and close many of those questions? What is the official guideline for dealing with these questions?
I'm speaking as an individual; the moderators haven't discussed this as a team.
There are currently 231 questions tagged sexuality, 206 of which are open. I doubt that all of them should be closed, though I wouldn't be surprised if some should be. By the way, another 141 have been deleted.
It's possible to ask questions about delicate topics in appropriate ways. Generally, the more clinical the question is, the better it fits. (Of course anything that seems to be seeking a personal ruling would already be close-worthy.) So "close all the sexuality questions" probably isn't the best response.
If you come across a question that you feel should be closed under our new close reason (or any other), please vote to close. If you want to spend some time reviewing older questions with this in mind, feel free. I'll ask that you not put 200 posts in the review queue all at once, just to keep the workload reasonable, but cleanup efforts are fine if you're thoughtfully evaluating each question.
If you feel a question is off-topic but could be fixed, and the user is still active on the site, consider leaving a comment explaining the issue. Closures don't generate notifications, and (speaking from personal experience) it can be a little disconcerting to visit one of your old questions and find that the community closed it without you even being aware so you could fix it. Use your judgement, of course; if you can't see how it could be fixed or the user hasn't been around in years, there's no point in pinging the person.