> Upside-down in the air is perfect.
> Swoop down with a hand outstretched, aiming at the back of the oni's head. Once we're two feet away from her head, fire a stream of our preferred shot type (arrowheads?) at the back of her head and slow down so we don't collide with her. If we see her starting to turn her head to look behind herself, however, fire our shots early. Tilting her head up is okay to keep waiting on, since she still won't be looking behind her; only fire prematurely with a left- or right-turn.