I think I've found the place to get my chicken ass fix. At Countryside Grill, P30 will get you a skewer of five small chicken asses. Your order will come with a bowl of spicy vinegar, into which you can dump all the chicken asses. If you're really hungry, ask for a spoon and start shoveling ass into your mouth like you would breakfast cereal. You won't find the need to spit out the bones because they're small enough to chew up and swallow. If something gets stuck in your throat, don't worry, a P25 beer will dislodge it quite nicely. If you're not into chicken ass, you can also get good old pork barbecue and tenga.
Get your fix along Katipunan, on the Ateneo-bound side, just before the fly-over. Dress comfortably (shorts and flip-flops).