Switched Centaur

During a violent lightening sorm and while in the midst of making passionate love on their wedding annicersary night, Melanie and Edward Sands are hit by a bolt of lightening. Fortunately, rather than being destroyed by the strike, their minds miraculousely survive but are flung far into the past of a parallel world.
When they wake up they discover that their minds had found refugein the bodies of very strange creatures--centaurs who possess half human and half horse bodies. As centaurs, they quickly discover, they possess both breeds' intense sexual desires and are driven to practice them constantly with multiple partners. But even stranger is the fact that in their haste to survive, each of their minds took on the body of an opposite gender, turning Edward into a female centaur and Melanie into a huge stud.
Once the shock of what had happened to them wears off, both accept it with great pleasure as they join the centaur herd and practice their strange lifestyle.