Try banding the main. U just take little sections of the main (make sure they are on the right side of course), take a rubber band and tie it tight. Then spray it wet.
Make it more thin and keep brushing it on that side when it's wet!👍
We always braid it over and put wet clothes on it for a while. Unless it really bothers you, you can always just do it for shows that way you don't have to worry about it sticking.
I get it wet, then brush it to one side until it dries, I also trim it frequently. :)
I tie my horses mane in a braid then I spray water into the mane to try and keep it there! It works for me but I always get my horses mane cut!
You can get wet rags and lay them on your horses mane. Make sure the mane is on the correct side when you lay the rags down. This will help overtime, however, I think braids help the best and the braids don't have to be tight.