To be a toy pony for a day, sounds like magic?  A toy pony, for a day; or, if you turn around it is forever.  Quite literally, if you excuse the pun.

A toy pony could be fun, if you bend that way.  If your barn doors swing in the right way.

There is a trick, as if it had been a Djinnie, behind the realization.  While the pony could be changed and adjusted, some changes can’t be reverted.  Only the original Pony could revert back.

Are you alone, no problem.

Is the companion not of age, options are available.  Do you prefer to have sex, that is quite acceptable.