Aside from human sex, there was Denobulan sex, Deltan sex, Vulcan sex, and Kingon sex. Denobulans practiced polygamy. Each Denobulan had three partners, and each of these had two other partners. Denobulans were liberal about sex, with sex occurring during Denobulan mating cycles. Deltans were so highly sexed they were forbidden from having sex while in Starfleet. Deltan sex was such an intense activity that a member of another species who had sex with a Deltan could go insane as a result. Vulcans were ruled by strict logic except every seven years during pon farr, which was the Vulcan mating cycle when a Vulcan lost all emotional control. Klingons: There is not a single thing about Klingon sex that could ever be described as gentle.