While fully conscious, I discovered my older sister was having multiple orgasms using my virgin penis! My protective instincts outweighed my sister's, leading to my virginity loss! HUNTB-038

My older sister, who is younger than me, is being cared for by my mother, and she always treats me like a child, overprotecting me! One day, as a virgin, I had a one-night stand with my sister, and I'm worried that she might gradually go from accepting it to pursuing her own pleasure...