I had a similar thing happen when I was 10.
I made friends with they new girl at school. Her name was Tiffany. She was also 10 and she was really fun to hang out with. I asked my mom if she could come for a sleepover. Tiff arrived Saturday afternoon and we spent a lot of time playing out doors and riding bikes. We rode out down a path into the woods. After a while we stopped in a secluded area and got off out bikes and sat down and had some water. We were talking about random shit when she asked me if riding a bike felt nice on my privates. I laughed and said not really, why does it feel good to you? Tiff goes Yea it make my vagina tingle. She goes, You know when you rub your vagina and it feels good, well this is like that. I looked at her and she goes You do touch yourself right? I was like Err yea sometimes. She goes Haven’t you even done anything with another friend? and I was going, Yes a few times. She goes Let’s go back to your house. I said OK and we got on our bikes and headed back. Soon as we got there she grabbed my hand and ran up to my room. My mom asked what were doing and she said We’re going to play a game. Mom said OK if you need anything just call because I’m going out in the backyard.
As soon as the door was closed, she locked it and lifted my t shirt and was rubbing my nipples. It felt nice. She took off her top and said Now you can do it to me. There we were rubbing each other nipples and it felt great. Then her hand moved down my front and into my shorts inside my underwear and she began feeling my pussy. It was the best experience I ever had. She rubbed and rubbed and finally her finger went right in me. After a minute or two she just pulled down my shorts and underwear and pushed me on the bed, opened my legs and started fingering me like crazy. I was loving it. She got up and took off her shorts. I noticed she wasn’t wearing any underwear and I commented and she said she prefers not to. She goes back to fingering me with one hand while fingering herself with the other. I’d never felt like this before. I told her I wanted to finger her so she lay back and opened her legs and I rubbed her clit and pushed my fingers in and out of her. I made her come several times. Then she goes, Lets try this and got us in a 69. She began licking me and I could feel her tongue on my clit. I followed her lead and began licking her out. We both had many orgasms and were feeling so good.
Tiff said we should get dressed and go see my mom so she didn’t get suspicious. I asked her if she had done all this before and she said that her female cousin who was 13 had shown her all this a few months before at a family party. They had snuck off to a quite place and her cousin showed her everything. Then she had done it was another friend some weeks later. But she said this was even better doing it with me.
We had a lot of sleepovers after that and even did it some afternoons after school. We also used to use our electric toothbrushes on each other.