The article is mainly based on a comprehensive collection of letters: “40 years of love letters”, which describes the intimate exchange between the – after the publication of the gymnastics book My System in 1904 – world-famous gymnastics educator Jørgen (Peter) Müller and his life partner Marie and much more about everyday life and body history especially in the 1890s. With this source material, we can get a unique insight into an erotic upheaval under Victorianism that has otherwise been almost hermetically closed to the curious glances of contemporaries, their descendants and modern historians. It is the main thesis of the article that Jørgen and Marie’s sensory experiences in their youth constitute a significant source of inspiration for: 1) Müller’s gymnastics system with its focus on skin massage, which helped to make Victorian people discover their own and each other’s bodies. 2) Müller’s book Sexual Morals and Life Happiness from 1908, which was one of the world’s first sexology books.