From an ad for the Teeter machines designed to stretch you out and make you feel better, a reference to the “benefits of inversion”.
Inversion has multiple senses, including some in linguistics, but also:
Sexual inversion is a term used by sexologists, primarily in the late 19th and early 20th century, to refer to homosexuality. Sexual inversion was believed to be an inborn reversal of gender traits: male inverts were, to a greater or lesser degree, inclined to traditionally female pursuits and dress and vice versa. The sexologist Richard Freiherr von Krafft-Ebing described female sexual inversion as “the masculine soul, heaving in the female bosom”. In its emphasis on gender role reversal, the theory of sexual inversion resembles transgender, which did not yet exist as a separate concept at the time.
Initially confined to medical texts, the concept of sexual inversion was given wide currency by Radclyffe Hall’s 1928 lesbian novel The Well of Loneliness, which was written in part to popularize the sexologists’ views. Published with a foreword by the sexologist Havelock Ellis, it consistently used the term “invert” to refer to its protagonist, who bore a strong resemblance to one of Krafft-Ebing’s case studies. (Wikipedia link)
In this quaint outmoded sense, I am a classic sexual invert. Ok, without the cross-sex identification.