My little sister has grown up to be my type, and she's very cute, but I thought she was a very serious girl who had nothing to do with sex, but she's actually a very lewd girl! At home, my defenseless little sister found out that I had an erection, and just when I thought she hated me, she got excited...she got so horny that she straddled me and shook her hips violently! She was so lewd that I couldn't imagine it from her usual seriousness, and she drooled and had a lewd expression on her face asking for my dick, and she used her hips so erotically that she came repeatedly and forced me to cum inside her with a high-speed grinding cowgirl position!