The Dominion Porn Industry

The closest thing Vorta or Jem'Hadar feel to sexual pleasure comes when they see a Changeling morph forms. There's a Dominion-wide underground industry selling holo-recordings of Changelings morphing from one form to another.

About 95% of the holo-recordings are clever fakes created by Vorta who've personally interacted with Founders and have seen them change forms. Another 4.5% are less-clever fakes created by the Ferengi. The remaining 0.5% are genuine. In addition to extra ketracel white rations, Vorta field supervisors show their Jem'Hadar these holo-recordings as a reward for good behavior or exceptional battlefield gallantry.

The Founders themselves are disgusted by the idea of solids gaining sexual gratification from their bodily functions and have made possessing such a holo-recording punishable by death. This dictate is largely unenforced outside the presence of a Founder.