This is the way I drew and will eventually paint a centaur. Throughout history centaurs have been depicted as having the head and torso of a man above the FULL body of a horse. Those proportions have always disturbed me--the horse's legs look like sticks beneath a muscular torso, for starters--and the "half-man, half-horse" definition really seemed to me more like "one-fourth man, three-fourths horse".
I've been fascinated with centaurs because Studio Antenor (my e-mail address) is named after the mentor of Florante, Adolfo, and Menandro in Francisco Baltazar's _Florante at Laura_. I have always believed him to be a centaur.
In my personal version, the spine of the centaur smoothly transits all the way to the horse's coccyx. The back of the horse is shorter but can still seat one rider. The centaur can reach all the way to his back and touch his tail, his butt, his dick, and all four hooves. And if I were a centaur I would like to be able to do all of that.