Whenever I visit my friend's house, his mom, "Ruri-san," always greets me. She's beautiful and kind... I secretly admired her. But there's one thing that bothered me. Her breasts were too big, even for me in puberty, making it hard to look away. One day, when I stayed over at my friend's place, I found Ruri-san sleeping unguarded on the couch. I couldn't help myself and started masturbating while staring at her body, so engrossed that I didn't even notice when she woke up...
