Think behaviour instead of just looks. Whereas most other token furries just hop around doing nothing, Boota has been right in the epicenter of the action from the beginning, supporting his master, giving encouraging speeches in the form of gurgling noises and arm wavings that still get the point across, and even gave up his own ass (literally) for his sake. Boota is a cute, snuggly valiant hero.
And yeah, boobs.
