As I was in my room, I noticed my stepsister's silhouette in the mirror. Intrigued, I glanced over and caught her flashing me, revealing her panties. She then proceeded to remove her dress, unveiling her flawless body. Overcome with lust, she began to pleasure herself, her hands exploring every inch of her. I couldn't resist the sight and joined in, our bodies entwined in a passionate embrace. The heat between us was palpable, our moans echoing in the room. Just as we reached our climax, there was a knock on the door, interrupting our intimate moment. We quickly dressed, attempting to conceal our illicit encounter. Later that night, as we returned from the social event, we couldn't help but reminisce about our secret rendezvous, our shared desire leaving us both yearning for more.