My little sister is a closet pervert who deliberately flashes her panties in front of me. I got turned on seeing her like that at the library, so I sneaked into her room to snoop through her underwear, but she suddenly came home and caught me. Panicking, I was about to run when she said, "I won't tell Mom if you give me a foot massage," while once again exposing her panties. My hand instinctively reached between her legs, touching her slit. We were both getting turned on, but we had to stop when Mom almost discovered us. The moment Mom left the house, our pent-up desires exploded. In the living room, my cock became rock hard, thrusting deep into her pussy as we had intense sex. My sister kept saying, "This is wrong—we're siblings," yet she kept losing control and pissing herself from excitement. But it's her fault for coming onto me in the first place.