Okay, I have time to write! This happened recently, two weekends ago.
I have written before about my wife's brother coming around barely twice a year or so, and she has teased him, which caused him to show up more often, but he hadn't been here since my last post about it, which was a long time ago.
Anyway, he was here two weekends ago to grill with us and my wife's family. During the part where we sit around in the yard and listen to her parents babble on about how we kids (despite being in our 40s) don't understand how the world is supposed to work, I started rubbing my wife's leg. She had a full-length skirt on, but her leg was crossed away from me, so I was able to take my opposite hand and rub her leg while rising her skirt until she would stop me, which I do a lot, so her family doesn't even notice that I do this anymore. I am good at making it look like an accident.
At one point, her parents wanted to walk to the end of the road with the youngest grandchild, and her brother was sitting across facing us, so I used that as an opportunity to raise her skirt higher. I got my hand up to her panties and snapped the elastic (at the bottom of the leg hole) and whispered in my wife's ear if that was okay, and she said, "It's fine until my parents get back." Remember that her brother was there, though, and he was staring at where my hand was the whole time.
So, I rubbed her hip and ass from inside the bottom of her panties, but not exposing them. I knew exactly what I was doing.
Just as her parents started coming into view, I pulled her skirt down, but I first pulled it up and then down so her brother could see her plain white panties before the show ended, and he certainly saw because his eyes got huge. My wife looked over at me. She knew what was going on.
Her parents came back and started complaining about stuff again, so my wife got up to go inside and get something, and I followed her.
She was standing at the sink, so I reached up her skirt and pulled her panties down, like I always do when I get a chance when people are over and she is in a long skirt. I asked if that was okay, and she said, "Just be extra careful, please!"
So we went back outside, and I didn't rub my wife's leg, because I didn't want to upset her on accident, of course.
Eventually her parents left, but her brother stayed. It was very weird for him to stay, but I am sure it's because he got a panty view and was wondering what else would happen. He even stayed long enough to help get the kids to bed!
He then sat on one couch while my wife sat on the other, and I sat on the floor giving her a foot rub. Then I worked my way up her legs, raising her skirt as I went. At one point she put her hand over her pussy to hold her skirt down, so that was my queue to be careful, so I was.
Then she put one leg up on the couch, but held her skirt down as to not show anything at all, while I was rubbing her opposite leg. She eventually leg go of her skirt, but it stayed in place.
I didn't know if this was a clue that she didn't care anymore, or was forgetting about it, so I kept rubbing higher and higher and she wasn't stopping me.
I got up to her hip of her left leg, and she looked down at me and smiled a clearly naughty smile, so I knew that was a clue that it was okay to have an "accident", so I let my wrist move her skirt up even more, exposing everything, but barely. I turned around and the look on her brother's face was amazing. His eyes almost popped out of his head and was frozen solid. My wife said, "Oh no!" and went upstairs. (I know it was part of her act.)
She came down later in pajamas, but they weren't any more conservative. These were pjs she has worn around him before. Within 5 minutes he saw her boobs when she bent over, lots of sideboob, and you could see clear up her shorts, giving a much more consistent show again anyway, but it seemed more innocent and casual in her pjs, despite being much more blatantly revealing than a long, conservative skirt, if that makes any sense.
A few minutes later she went to bed and he suddenly left as well. No texts from him afterwards this time, though!