My nosy big-breasted kind-hearted sister found out that I had my first girlfriend and taught me a simulation of my first sex! Since I've never even kissed before, let alone seen a vagina or breasts, she taught me the flow up to insertion, but I was still anxious. 'Just this once is okay,' she promised, so I tried inserting just once, but even one time felt so good in an actual vagina that I found myself thrusting my hips multiple times! My sister, now completely aroused, demanded my dick and made me cum inside her multiple times.
