This is a great idea for a thread - these kinds of events are pretty much my favorite. Fortunately, I have one in mind to share.
This was back in 2015. Me, my wife and a male friend of ours (more a friend of mine I guess, as they never hung out one-on-one or anything and I actually knew him before her, but they got on just fine), being the dorks we all are, drove a few hours to the adjacent city for Comic-Con, where we were all going to share a hotel room for two nights. We didn't spend too much time at all in the hotel room, too much other stuff to do, but the arrangement, from left to right if you were to stand where the TV was and face forward, was that my wife and I had the bed farthest from the door and bathroom, me the farthest towards the wall, then her, then our friend on the next bed over, then the bathroom and the door.
The first night my wife slept in an old t-shirt and panties, and I was actually super excited by the couple of minutes she spent in the hotel room that night walking around in that in front of my friend (little did I know how much better it would get!). In the morning we all woke up to an alarm and my and my wife looked at our phones for a few minutes while my friend looked at his laptop. Then my wife got out of bed and walked past my friend in his bed and into the bathroom, grabbing her pre-set out Star Trek outfit off the back of a chair on the way. After the sound of a quick shower and brushing her teeth she emerged in her outfit, told us the bathroom was now open, and went and started putting on makeup in the mirror.
Later that day she told me that, except for a couple times she shared a hotel room with her parents, that had been the first time she'd slept in a bed with a top on since she had a roommate her freshman year of college almost ten years ago, and she'd had trouble falling asleep wearing one. I told her that she should take the top off after the lights are off and she was under the covers, and she was like "Hm, maybe."
So that night she again walked around for a few minutes in front of my friend in her shirt and panties and did just what I suggested after the lights went off and she was under the covers and lost the top. Again, pretty exciting, though it really did get very dark with the light off and I'm sure our friend saw nothing of that.
In the morning, though... here's where things get interesting. Again, the alarm went off and we kind of looked at our phones/laptop for a few minutes in bed. At first my wife kept the covers pulled up right to her chin but over the next ten or so minutes they gradually drifted, drifted down - first her upper shoulders exposed, then her whole shoulders (this was around when I, trying to play it cool, definitely noticed my friend notice, as his previous casual looking over at us and talking about the day's plans suddenly turned a bit more stiff and formal, HIM trying to play it cool), then she sat up and the top of her breasts said hello as the top of the sheet was resting probably an inch above her nipple.
After looking at her phone for a couple more minutes like this, she went "Well, time to get ready," and, over the course of the next thirty seconds that I still remember/think/fantasize about at least once a week two years later, she slipped out of the covers, gently swung her legs over the edge of the bed and sat up, topless in panties in the soft morning light and her naked upper body facing our friend, sat there for about ten seconds in a sleepyheaded shaking-off-the-cobwebs sort of way, then stood up, unhurriedly walked past our friend topless, grabbed her outfit and again disappeared into the bathroom and shut the door.
A few moments passed in silence, and my friend cleared his throat and spoke up: "Uh, she's not shy."
NOPE!
