I uncover my stepsister's lesbian secret despite her claiming to be straight

My sister's best friend is a lesbian, but she denies it every time. I stumbled upon some evidence that proved her secret, and now, we're both exploring her sexuality.

I was on my way back when I saw her through the window, her clothes all in disarray. My heart raced as I realized what was happening. My stepsister, a girl I thought was straight, was having lesbian sex with another woman. I couldn't believe it at first, but the sight of her writhing in pleasure was too much to ignore. I had to know more, to uncover the truth behind this taboo secret. I crept closer, my heart pounding in my chest as I listened to their moans of pleasure. They were lost in their own world, their bodies entwined in a passionate embrace. I couldn't resist the urge to join them, to be a part of their forbidden love. My stepsister, once a mystery to me, revealed herself to be a wild, passionate lover, a woman who knew exactly how to push my boundaries. As we explored each other's bodies, I felt a new kind of pleasure coursing through me, a pleasure that transcended all taboos.