Well, I can't be sure, but I don't think they ever did- at least not while we were seeing each other LOL. I was surprised when she mentioned thinking that way about her brother, but CERTAINLY didn't seem disapproving, as I would have been thrilled if she'd told me they had!
In fact I thought about suggesting it many times but never did, because I didn't want to risk her thinking too hard about what she HAD done to that point and maybe stopping. And at the time he was innocent enough that I was sure he'd never initiate any physical contact.
That didn't mean he never touched her though
But that was my doing- we were heading to the beach one afternoon and her mother "suggested" we take her brother along (I thought at the time to act as a chaperone). Well, it did sort of prevent us from our usual routine: on the 15 minute or so drive I had gotten into the habit of getting my GF to untie her bikini top and let a few truck drivers get a look at her bare tits just to get her hot and horny for the beach. Instead I told her to plan on changing in the car-- she packed her bikini and off the three of us went.
Now there was a changing place at the beach, but it was pretty rundown and dirty, and when we arrived she said she didn't want to even go in there, and would change in the car instead. Her brother and I got out and turned our backs in a gentlemanly fashion (HAH!) while she started to change. After a moment, I looked at her brother with a grin and sort of nodded my head back toward the car. He got kind of a nervous smile and I slowly turned my head a little until I could start to see her, then I grinned back at him and nodded again then turned some more. He got the idea and also turned bit by bit toward her. The car was low enough that we could see her easily from the shoulders down, but not her face- which meant she couldn't see us looking at her. So we got to enjoy her taking off ALL her clothes, then wiggling into her bikini- this was the first time we'd ever BOTH been looking at her when she was exposed, and it was HOT.
We managed not to get busted watching her change, and got down to the beach and set up towels and a cooler, etc. Dick went into the water right away- probably to cool down LOL and I told her what we'd done and seen as she changed. She laughed and said she figured we'd be looking and asked if her brother enjoyed her show- HELL YES was my answer-
She tormented him all afternoon, untying her bikini top and raising up on her elbows to read a magazine, with her pale tits and stiff pink nipples absolutely bare in front of her kid brother on the towel right next to her- two feet away? I could hardly keep from cumming on the spot LOL and he was much the same I'd guess. She had me put lotion on her bare back and legs and he enjoyed watching that as well. The only other thing tat happened was that she also had her brother rub lotion on her when I was wading in the lake- so he got to spend some time with his hands on her.
I was watching but couldn't see much, but later she told me he started at her feet and took about 10 seconds to get to her thighs-which she opened wide for him (she was on her stomach) then spent about a minute there LOL even getting his hands on the soft inner parts of her upper thighs right next to her pussy! She was getting pretty hot, and when started on her lower back she raised up on her elbows again so her tits were off the towel. He did a very thorough job on her back, and moved around to each side of her to get the best possible look at her bare tits- and even let the tips of his fingers slide along her sides from her waist up toward her arms! She said he never tried to reach around to her tits, but had his hands enough on her sides to lightly touch the out parts of the sides of her breasts! She told me her nipples had never been so sensitive as then, and thought if he'd touched them she would have had a orgasm immediately LOL
When I dropped them off later, her mother asked Dick if he'd had a good time....
I found this photo today; it's not the girl in these stories, but like the video stills I posted some time ago, this girl could be my ex-GF's sister (although my ex had perkier tits) and I thought people might enjoy another visual to match with the stories--think of having a cute older sister who liked to let you see her like this!