Solid steel butt plug pony tail with real horse hair. Photo by cpony. Tails can be sub-divided into two broad categories: butt plug and non-butt plug. The materials used for ponyplay tails varies considerably: from cheap synthetic material to real horsehair. Moreover, the quality of the plug portion of butt plug tails also varies considerably with the nicer ones having metal or glass plugs. The image at the right on top illustrates a quality metal butt plug tail with real horse hair for the tail portion.