Mizuki Yayoi, with her plump, big breasts, appears in this popular series that develops a woman's new erogenous zone, the Spence's gland! The Spence's gland is the G-spot of the breast! A specialist in Spence's gland research has developed it, and she experiences her first breast orgasm, something she has never experienced before! She is half-believing the development of her gland, but it makes her arch her back in orgasm, and her nipples are teased as she has sex with her Spence stimulated and she cums inside! She is relentlessly toyed with, and she has a downpour of incontinence and convulsions! A titty fuck that brings her to orgasm as the mammary gland rubs against her! Nipple teasing is allowed, and she finally faints and ascends to heaven with hip-bouncing, squirting sex!