When I took a bath with my sister for the first time in a while on a family trip, I got a full erection from her beautiful big breasts, which were bigger than I had imagined! I was a virgin, but I tried to hide it, but she found out. I was embarrassed anyway, so I asked her for a lifetime of love, "Let me do it!" She took pity on me and even got down on the ground, so she reluctantly agreed. I enjoyed losing my virginity while rubbing her big breasts!