Me and my sister were in the pool and when we got out I realized my clothes were in the drier. I waited in just a towel on the couch watching tv with my little sister. We had no remote, so I had to keep getting up to change the channel.
Once, on my way back to the couch, my towel slipped and my little sister saw my 'privates'. She was instantly curious and asked why did hair grow down there? Why does hair grow on your head? I asked. I was hard because my sister saw my privates. She saw and asked if it bent.
She told me to touch it and she thought it was gross. She eventually touched it and I showed her how to rub it. She did not do it perfectly but just having another person touch it made me go over. She was rubbing for two more minutes before I had the best orgasm of my life. We never did it again, and never spoke about it.