I've always been drawn to my stepsister's voluptuous derriere. It's a sight that never fails to captivate me. One day, as we were both lounging around the house, I couldn't resist the allure of her round, firm buttocks. I found myself reaching out to touch it, my fingers tracing the curve of her pantie-clad rear. She didn't object, and the sensation of her soft skin under my touch was intoxicating. As things heated up, I found myself unable to resist the urge to explore further. I moved my hand beneath her panties, feeling the heat radiating from her body. My touch sent shivers down her spine, and I knew I had to take things to the next level. I began to kiss her neck, my lips lingering on her delicate skin. She moaned in pleasure, her body arching towards mine. The sight of her ample bosom heaving with each breath she took only fueled my desire. I knew then that this was more than just a fleeting moment of passion. It was the start of a whole new adventure.