I make these all the time for my daughter. I guess I should really make a tut for this.
You need to lay you're ribbon out just like you do you're spikes for stacked bows. Then pinch the middle just like you do on a twisted boutique bow. Then sew, or tie to you're liking. Then attactch you're pony o. Finish off with a 3/8 ribbon to hide the middle just like with a boutique bow.
I will try and post pics of all the streamers I make!