Here are some of the official definitions from this site:
Subtypes - Enneagram Monthly
"The sexual instinct strives towards syntony with the world, to be in tune and vibrate with it; you have to cover a lot of space, emit the strongest and pick up the subtlest signals when searching for the most or best of mates.
Sexual (SX):
• Vibrating out there, looking for a mate; peacock displaying his feathers, deer locking antlers
• Susceptibility to states of intoxication, tripping
• Schizoid disposition (split between affect and intellect, invalidating one with the other)
• Lightness, playfulness
• Curious, seeking, searching
• Often has shiny, leaky eyes (leaking the high energy of sexuality)
• Not about orgasm (which one can have alone) but about letting go, dropping barriers, intimacy, closeness, union through revealing/denuding oneself
• Madonna or whore, abstinent or promiscuous
• Frigid or impotent, unusual sexual preferences
• Crime of passion
• Least likely to become famous (SP goes for immortality, SO intent on glory; SX has other things to do)
• SX: I have the power to attract whomever I choose and I know what passion means. I am in tune with the world around, sense its vibrations, and am ready to respond when my mate calls.
• SX: Through union with the One I can transcend myself, achieve wholeness (oneness with myself; I’m the half of a pair)
• SX: To be intimate or not to be intimate; how to be intimate"
There's a lot more on that link with specific questions and issues answered by each of the variants.
Wow, it just occurred to me that "Closer" by NIN defines this rather perfectly.