My younger sister Zoe has precocious puberty which is why she began to develop breast buds aged 6
I quickly noticed that she was growing and before very long I started getting excited and getting erections for her I knew it was wrong but I couldn't stop it happening it would get so hard it was aching and throbbing and the only way I could get any relief was to play with myself.
I didn't try and hide what I was doing from Zoe as I would sit on the sofa with her watching as I was rubbing and fondling my bulge in my trousers