悪意のないところが憎めないのだが普段から何かと騒がしい天然の黒ギャル巨乳姉。僕が勉強している背後でとうとうオナニーまでするようになった。試験も近いため気にしないようにしていたのに、本人は無自覚なオホ声がバカでかくて全く集中できない！僕はオナ禁で受験勉強しているというのに、、、溜めていた性欲と怒りが沸点に到達！！オナニーでイッた直後の感度 MAXま○こに即ハメした！不意を突かれアヘ顔潮射イキ！いつもは強気な姉がヘトヘトに立てなくなるまで中出しピストンを続けた！

My big-breasted, naturally quirky, dark-skinned gyaru older sister is endearing because she doesn't mean any harm, but she's always noisy about everything. Now she's even started masturbating behind me while I'm studying. I've been trying not to let it bother me because exams are coming up, but her unaware moans are so loud I can't concentrate at all! I'm supposed to be abstaining from masturbation to study for my exams, but… my pent-up sexual desire and anger have reached their boiling point!! I immediately fucked her pussy, which was at its most sensitive right after she came from masturbating! Caught off guard, she came with an ecstatic, squirting orgasm! I continued to fuck her until my usually strong-willed sister was so exhausted she could barely stand!