I saw both my mother and sister in law naked and loved both viewings... They didn't happen at the same time and I haven't had sex with either one... although.. the thoughts are there and I wouldn't say no, if asked by one of them.........
We had a family event to go to out of town. The wife and I booked a room at the same hotel that the m and f in law were staying at.
In the morning of the event, the wife said she had to go and talk to mom, since we were already to go, I tagged along to the room and would chat up dad...