This is what I do for frizz;
1. Wet pony hair completely.
2. Shampoo hair thoroughly, like you would your own.
3. Rinse out shampoo.
4. Combine some anti-frizz serum and a gentle, natural conditioner and mix it up with a cocktail stick.
5. Massage anti-frizz concoction into pony hair and allow to sit for a minimum of 5 minutes.
6. There's two things I do. Either
a) rinse out conditioner and style
b) the
boiling method.
The Boiling Method
1. Boil up some water (do NOT rinse conditioner out of the pony hair)
2. Leave the water to boil and, minding to not get burnt, slowly dip the pony hair into the water (I wear gardening gloves to be safe)
3. Let the hair sit for a good minute.
4. Pull out hair and comb the mane out flat.
The boiling method looks extremely soft and silky and straight, but not boiling allows you to style.
To dry I focus a lamp on the pony until dry, and then if its styled I spritz with a good hair-spray, then allow to set for an hour.
Just DON'T boil colour changing hair.