Spandex fetishism

Spandex fetishism is a fetishistic attraction to people wearing form-fitting stretch fabrics or to the wearing of items of clothing made of such material.

Spandex garments are often worn by swimmers, gymnasts, ballet dancers, wrestlers, rowers, cyclists, contortionists and circus performers, and spandex fetishists may incorporate fantasies about these activities into their particular fetish.

Wearers of skin-tight nylon and cotton spandex garments can appear naked or coated in a shiny or matte substance like paint.

Another reason, at least pertinent to nylon-spandex fabric, is that the material can have a very smooth and silk-like finish, which lends a tactile dimension to the fetish - as well as a visual one.

[1] The pressure of tight garments against the genitals can become quite sensual.