I never did a doubles before.....but I definitely understand the need to change condoms especially when it comes to sex and multiple positions. I don't mind switching....and compared to a session the price of condoms is relatively cheap....I usually bring my own though. Every now and then you might run into a provider who stingy with her condoms and hesitant to give you yet another one when it pops....so I bring my own always. Same thing with ladies on incalls who are stingy with extra towels........that's why I do outcalls.
Now if both ladies were alternating giving me BBBJ and one decided to wipe my dick off first so she could go next......id be dissaaapointed and the fantasy of being with two chicks is non existent. It would suck also if I went down on one....and was blocked by the other.....or went down on one and blocked from kissing the other.........too many restrictions......