My girlfriend of six months isn't particularly into sex and has a well-behaved, studious personality. Her older sister, however, is the complete opposite—mature, carefree, and irresistibly alluring. Whenever we're alone, she instantly seduces me. Even with my girlfriend nearby, she teases me boldly, whispering sweet nothings in my ear while pressing her erotic body against mine. Every time I touch her skin, it sends my heart racing. Over three intense days, we engaged in sweaty, passionate sex—she squirted repeatedly, drenching me completely as we kept making love. That shocking experience left me completely addicted to her.