In my late teens, I began to get curious about how my little sister was developing. We were fairly close, but it still would have been very awkward if I just flat out asked to see her naked. One night, she was in my room and somehow the conversation led to puberty, so I subtly asked her how her body was changing.
She said her breasts had definitely grown in the past few years and she now had pubic hair. Curious, I realised this would be a good time to ask if I could see her naked. When I asked she had a look of nervousness and reluctance, which I thought she would have. To ease her somewhat, I told her she didn’t have to do anything and could forget about it.
To my slight surprise she said she would show me just this once as long as she could see my penis as well. I agreed and we both hurried to the bathroom. It was midnight and our parents were asleep, but we had to be quick about it in case one of them had to use the bathroom.
We closed and locked the bathroom door and I took off all my clothes and sat cross-legged on the floor. My sister remained standing, dropped her shorts and panties to her ankles and lifted her shirt up to reveal her boobs. My sister’s breasts popped out much more than before with large puffy nipples. Her pussy was larger and had much more pubic hair than I was expecting.
I got an erection straight away and proceeded to jerk off quickly. My sister stared at my privates, curious. While I came quickly, not much came out - I guess due to the nervous and slightly awkward nature of the situation. When I finished and cleaned myself up I thanked my sister and she said the same to me.
We never did anything like that again but I appreciate her for giving me a quick show!