No matter what I did, she never got angry; she was just incredibly kind and had huge breasts. When I confided in her that 'I'm the only virgin left in my class,' she said if it's just rubbing, then she'd let me do it, so we did some frottage! As a virgin, I was super excited and desperately rubbed my dick against her. Then her pussy started getting wet... 'It feels like it might go in, stop!' But I couldn't stop my hips, and it slid right in! Since kind sister naturally forgave me, I got carried away and kept cumming inside her until I was completely spent!
