My stepmother has H-cup breasts, and her appearance and figure were so overwhelming for me, a virgin, that I couldn't stop feeling nervous just being around her. During a family trip to a hot spring, I unexpectedly lost my virginity to her in the bathroom—an experience I'll never forget. Sneaking into her room, I passionately groped her soft, large breasts while my father was just next door, which only heightened my excitement. Spoiled by her breastfeeding, handjob, and massive titty fuck, I couldn't hold back and pounded her from behind in cowgirl position, slamming her ass hard. Grabbing her big ass tightly from behind, I thrust into her deeply, unable to resist the tight grip of her clinging pussy, and ended up cumming inside her bare. Caught between the tension of the moment and the forbidden nature of our relationship, my physical desires became impossible to control.