Try this article: http://www.guycribb.com/userfiles/documents/EarlyPlaning.pdf
The most basic pumping consists of pulling a few times with your backhand while hooked in. It is easy to do, and is often enough to get you over the planning threshold.
The next step is pumping with both hands and your whole body (as described by Cribb). It is much more efficient, but also a lot harder to get the technique right.