The HV20 comes with a manual focus roller, which is a good thing. However, it is a bit awkward to operate.
Others here and in HV20.com have come up with clever ways to get around this problem. They usually involve larger wheels that are mounted on some assembly. The wheels are designed to touch the roller and turn it by way of friction.
Here is a minimalist friction tool that can be used to accomplish the same task (well, perhaps with enough practice). It is small, portable, cheap, and light-weight.
See more DOF sample videos using the stick: