Sprinkle a little sawdust on the spot and give the spot a little attention from your does weed and feed work hose. The sawdust will hide the poop and it will counter the excess nitrogen.
Combining with the nitrogen, it will, in time, turn into compost – enriching the soil. The water will wet the sawdust and dilute the nitrogen source a bit, thus helping the grass diease beginning of the composting process. Consider for a moment that if you have a lot of mushrooms in your lawn, this is most likely a sign that you have really excellent soil!