In the first place, a Sybian is a device which causes any guy upon encountering it to start humming “Back In The Saddle Again” by Gene Autry.
It does, after all, resemble a saddle. It’s a masturbation device which ladies sit on. It sprouts an upright shaft for penetration, a ridge for clitoral contact, and a vibrating motor. So it’s basically a vibrating saddle with a dildo built in. You plug it in and gallop away. Some models contain more gizmos and tweaks; a variable-speed control is common. There’s also an assortment of interchangeable attachments, for users looking for a better fit.
The Sybian was invented by Dave Lampert, who thought of the idea in the 1970s and developed a prototype by 1983. He’d noticed that girl-on-top was a better position for female orgasms, as anybody who’s tried the “cowgirl” position can tell you. The device was built not as an end for itself, but to help gals practice being better riders on a man, and to help them become better at multiple orgasms.
By the time the Sybian was released in 1987, it was introduced in Penthouse magazine. It built up a little fame through the turn of the century, but it really gained fame in 2006 when somebody gave one to radio shock-jock Howard Stern, who kept the device in his studio and regularly invited female guests to ride it while on the air.
David Lampert himself participates in the marketing of the device, writing guest blog posts for various adult toy sites marketing his product. You have to like a man who stands by his work!
By the way, the bit about helping women train for sexual fitness is actually a real concern. Riding a Sybian (or having cowgirl sex) is great exercise, helping tone up the thigh and groin region. It also helps maintain those pelvic floor muscles, without which women can experience problems like incontinence later in life. Even just plain vibrators are sometimes prescribed by doctors to re-awaken sexual libido and stimulate pelvic blood flow, which does become an issue with maturity. While Sybians, being one of the more expensive sex toys out there, aren’t prescribed just yet, there’s not much reason one can see why they aren’t just as good a substitute.