I happen to have a copy of the old codex chaos space marines let me recite the book of Slaanesh:
"The hearts of mortals harbor the darkest of desires and it is in Slaanesh that these desires find expression. Every culture imposes limits and standards on its peoples: Slaanesh is the manifestation of the desire to stretch these limits to breaking point, to exceed them, and to wallow in the act of violating every more of civilized society."
"Slaanesh whispers to man in many different voices: each whisper attuned to the most secret desire of the listener. Many desire perfection, weather in intellect, the body, or ability, and Slaanesh will grant these individuals the power and drive to hone their desires to the utmost excellence. The artist will produce works beyond human comprehension, the narcissist hones their visage so that other mortals are driven insane with desire, and the warrior develops such abilities so that a casual gesture may decapitate the mightiest of foes. To the followers of Slaanesh the material world is a riot of colour, sound and sensation. However, their senses soon become accustomed to these levels of stimulation and they are driven to extremes in search of the slightest fulfillment."
"The followers of Slaanesh often exhibit the utmost physical perfection to the naked eye, and on the exterior it may be true that no mortal is capable of such beauty. But the soul of each follower screams in eternal torment as the gifts bestowed by the Prince of Chaos are purchased at a price as high as that demanded by any other Chaos God: eternal damnation. "
"Slaanesh may appaear as male, female, hermaphrodite or androgynous. Which ever form he takes, his physical beuty is such that no mortal may look upon him and resist the urge to submit."
That is exactly how Slaanesh is described in the past Codex. No where does it discuss sex and nudity to worship Slaanesh.
