You could wrap the hair and spray it, but if your pony already has hair I'd say a brush on is probably best. I mix mine with water and do a few very thin coats. You can use a brush or a sponge. I like the sponge better to avoid uneven strokes, but not everyone does.
Many people seal full body repaints before doing symbol or eye work. That way if carefully done the top coat could be removed, leaving the fbr intact.
Edit: never try to seal before your pony is 100% dry in my experience. It's like when you do multiple coats, if it's not dry it will streak and clump up.