If you use evel II you can see the bunching clearly, to me it is a little confusing (and often "painted", but at critical junction, you just see the rapid rise of the size on the ask or the rapid rise of the size on the bid, also the rate at which big size is "eaten up" is also an indication. It is far from being foolproof and I have been fooled more than once (in one day <g>). But I use this as very short term timing indicator after I have made a decision that a turn (up or down) is about to occur.
Zeev