My Mooky does the same thing. We have been letting the cats out on the back balony, supervised, for some fresh air, about 3 times now and then bring them in about an hour later.
Within half an hour, Mooky will start meowing, meowing, meowing to go back out and Sades will stretch up and tap on the door handle. I swear he is trying to learn how to turn the doorknob.
So, Pouncer is just letting you know that he wants to go outside.
Maybe if you let him out for a little bit with you watching him, it might satisfied him.