Kahn-ut-tu

Nona, a Kahn-ut-tu of Tyree's tribe performs a ritualistic ceremony with a mahko root.

The Kahn-ut-tu were female members of the Hill People of planet Neural who were trained as healers. They were skilled in the plant biology of the planet and knew which roots and herbs would cure certain ailments. These medicinal plants were then combined with shamanistic rituals during the healing process. Most notable of these was the mahko root ceremony used to extract Mugato venom from an infected individual. Kahn-ut-tu women had very high status in their tribes and were highly sought after as mates. According to regional legend no man could refuse a Kahn-ut-tu once he had been through a medicinal ritual with one.

One Kahn-ut-tu, Nona, demonstrated knowledge of a plant that emitted an airborne compound capable of inducing lust in males. She used this to control her husband, and attempted the same on Captain Kirk. (TOS: "A Private Little War")

There may have been an unseen force (biological or otherwise) that made them particularly attractive following the ritual.