This happened to me several years ago.
I was invited over to some friends house for dinner. My folks were out of town and I guess they felt sorry for me and wanted to feed me.
I arrived at their house about 5:30 in the evening. No one was there except the daughter who I would guess was a senior in high school although she looked a tad younger.
Her folks were not home from work yet but she invited me in and we went into the living room and sat on down to wait for her parents to arrive. We engaged in some small talk, something about school and did she have any boyfriends.
Soon she came over to the couch where I was sitting and sat down beside me. She seemed very, very friendly and flirty. After a bit, she put her hand on my knee and squeezed it. What a shock! This sent a bolt of excitement up my leg to my groin. I wondered what the heck was going on. She sort of giggled a bit and did it again. Only this time just a bit higher on my leg. I thought, WOW, this is neat. She wants to be friendly and play. So I reached over and gave her knee a squeeze in return. Her legs went apart just a bit and she reached for my leg again and squeezed just a bit higher. So I did likewise to her. We were getting about mid-thigh by now and the excitement in my groin was growing very intense.
We continued squeezing each other's legs until we were about as high as you can go, almost touching each other's private parts. She was giggling all the while having a great time of it.
In a bit she got up and headed to a hallway door and turned down a hall. I stood up and followed her to the hall door to see where she was headed. She turned into the bathroom stopping at the door to see if I was coming. I was. We both entered the bathroom and she locked the door behind us. She then sat on the toilet seat, leaned back, stretched her legs out full and spread them about half way open.
We chatted for a few minutes then she took her dress about mid-thigh and began to pull it up her legs. Then she would let it down. She pulled it up again, this time a little higher. My heart was beginning to pound in my chest. She had gorgeous legs. Nice and full and tan. Then she let the hem down. On the third pull, she went all the way so that the hem was just high enough so that I could see the crotch of her panties. It was shining with wetness.
She left the hem there and opened her legs almost as far as they would go. With her eyes now shut she reached her hand down and began to rub her wet panties with her middle finger. Up and down her panty crotch.
I watched her for a minute or two. She was really enjoying it. After a minute of two I asked if she wanted me to do it. She opened her eyes and invited my hand to her panties. I rubbed up and down just as she had done. He hips now starting to undulate to the rhythm of my finger as I rubbed her panties with her slit just under the wet panty crotch.
It didn't take but a minute or two of this and she began to moan, her hips rocking rapidly now and my finger going up and down her crack just as fast. She started to cum and her hips now were gyrating wildly as she let out moan after moan.
As soon as she came down from her orgasm, she closed her legs, pulled her dress down and we left the bathroom. Her folks soon came and we ate dinner and I left. Nothing more was said.
This happened but once and I will never forget this pretty little girl allowing me such intimacy with her.