Its quite possible to wear hoof soaking boots as human pony play boots. Add a rigid rod to keep the pony form bending his foot and some polos and you have a very secure hoof boot.

Pink polos securing hoof soaking boots to my feet. Photo by cpony.com

Polos, also called polo wraps or simply wraps (though this can refer to other types of wraps), are lengths of cloth, often with Velcro at the ends to be fixed in place, which are wrapped around a pony's limbs to protect the pony's limbs from damage, add support, or restrict limb movement. If you really want to pamper your pony, Hermes makes polos (along with brushes, saddles, and many, many non-horse things).