Sometimes when my father went on business, my sister would invite her friend Silvia to spend the night at our house. Since my sister and I shared a room, I'd sleep with my mother on those occasions, and Silvia would sleep in my bed. It was on one of those occasions that I, spying as I usually do, saw my sister and Silvia showering together, and I assure you, it was an unforgettable sight. Seeing them naked, soaping each other up (even in very intimate areas) made me realize that, in addition to their passion for cock, these two weren't above engaging in a very discreet lesbian encounter. Knowing that they, too, had bisexual desires made me feel less "weird" and gave me the courage to embrace my own desires.