IENE-847 - Sister promised it was just rubbing, but ended up fully penetrating her

My younger sister, a high school girl, took pity on me for not having any sex, so she promised me that she would just rub me, so I asked her to do it with me, and it felt so good that our pussies were soaking wet! Insert it raw! "What!? Is it inside?" But I can't stop and cum! Urara Kanon