Rio and I have been dating for three months. This is the first time I visit her house and also the first time I meet her sister, Anna. She has a beautiful face and a charming figure. While we were studying, she suddenly raised her leg, revealing the space between her thighs. What? No panties?! That's right! I could clearly see her beautiful pussy. She intentionally opened wider and posed in a seductive way to tease me. And when my girlfriend was away, she approached me and skillfully seduced me. I lost all reason and my cock couldn't stop plunging deep into that inviting pussy. I love my girlfriend, but her sister gives me pleasure that I've never experienced before. And since then, we secretly have sex with each other every time my girlfriend is away...