If you look at a feather, you'll notice the barbs point in the direction of the tip of the feather. When palmered (i.e., wrapped) around the body of a woolly bugger, the feather barbs will want to maintain this orientation.

Thus, if you want your woolly bugger feather barbs to point towards the rear of the fly, either (i) tie in the base of the feather at the head of the fly and wrap backwards towards the tail of the fly (Jbird's method) or (ii) tie in the tip of the feather at the tail tie-in point and wrap the feather forward toward the head of the fly. With either method, the tip of the feather will end up at the tail of the fly, and the feather barbs will naturally orient in that direction.