Buy some puts? Are you trying to lock in a gain or just protected yourself from downside? Is this because of what is currently going on in the market? At the moment, insurance is a bit expensive. Reduce your exposure to small/micros? Mix your allocation into a relatively uncorrelated asset? Just random thoughts.
IWM if you're new to options. Perhaps RUT is you've been around. Also, I'll agree the barn door's been open for a few days now and the horses are running all over. You might want to see how this bounce plays out before putting on your position.