Sister and Stepdad Let Me Join Their Secret Hookups for My Birthday

I couldn't wait to turn eighteen and now I know why everyone said it would be so much fun. My stepdad and Sister have apparently been hooking up for a while and now that I'm old enough they finally let me join them. The second my Sister took my top off and my stepdad touched me I knew this was going to be the best birthday ever and I can't wait to try everything they want to teach me.