My cute but unattractive little sister became a college student and started researching fashion that would attract men, and she started wearing a cute knit dress and knee-high socks! Even though I knew it was my sister, I got a boner when I saw her thighs and panties through her short dress! She also stuck out her butt unprotectedly, so I thought she was trying to seduce me, and I ended up inserting it into her from behind and cumming inside her. From that day on, my sister became addicted to cumming inside her, and she became a slut who would keep seducing men in her knit dress!