1.1) Would you share your bed with a person of the same sex?
Yes, if I know them. It might be a bit weird if I don't know the person, but I'd be okay with it. And have been, for that matter, on various trips and such where a bunch of us share a hotel room.
2) Can you openly talk about sex or sexuality?
To an extent. You have to understand (or at least you should, though many people refuse), for some people, sex is an important thing in relationships, indicative of intense marriage-level commitment. Under that meaning, sex takes on a certain level of sanctity, if you will; it is a good thing, but only when used in the right context and for the right reasons. This means, based on this worldview, that it can be talked about and discussed, but should be treated as the important and valuable thing that it is (not that this eliminates the intermittent "that's what she said"). So I can openly discuss it (unlike what most people seem to think about people like me, I do think it's an amazing and valuable thing), but I do not agree with how flippantly our culture as a whole treats the subject.
3) How do you act around up-tight people?
I just... don't talk about sex. It's not tough. No "that's what she said" jokes or anything like that; try to avoid the subject altogether, and if it comes up, treat it with the importance and reverence for which the subject calls.