I can understand what's going on. My fiancee has a gf that she's been close to since they were 15 (they're 22 now) and she's always been uncomfortable telling me about anything sexual they do together. I knew she was actively bi when I started dating her and she spends the night with J once or twice a month and I'm happy she does since J is also a good friend of mine. I've always been curious and wanting to talk about it but she says its a personal thing between the two of them and she doesn't feel like she should share with another person. I think it would be a very intimate thing.
I've only been there once when they had sex and it was much like what we do together - lots of cuddling and kissing and touching, oral back and forth followed by penetrative sex, which they did for each other. I'm less curious about it now but I would still like to talk about it.
I understand, too, about being surrounded by conservative family and friends and having to hide our relationships. We took a trip to see her family up north and the only one who knows is an aunt who actually approves. The rest are fundamentalists.