I can't think of anything particularity "weird." I did have an ex boyfriend call out his ex's name while in bed. That didn't go over well to say the least.
I wore my gf's bra once... it felt nice! Then just as we were getting it on, she noticed I was still wearing it, I forgot I had it on, no rly! So I took it off, but it didn't arf feel weird taking her bra off (myself) while having sex with her :uhoh2: