Advance your thread forward to the half-way point of the hook shank.
Palmer the marabou forward being careful to not bind any fibers underneath each wrap. Stop and tie it off before you get to the thick brittle stem of the feather, using 5 wraps over the marabou then three behind before trimming the excess stem and feather. Straighten and make sure the fibers wrapped neatly then blow or use your left hand to pull the fibers back evenly. Brian Wise has a few awesome videos on you tube showing this technique. https://www.youtube.com/watch?v=SlSvnycHDZE&feature=c4-overview-vl&list=PL550F52FC398332B2