Pee In The Potty

A few days ago when Bulldozer woke up I asked him if he'd like to wear his "big boy underwear". He very enthusiastically said "YES!". I had bought him Hanes boxer-briefs to look just like Daddy - yes people, you know what my Husband wears! The underwear were adorable, multi-coloured with the band of elastic just like adult underwear. So we start out with boxers number one. Bulldozer is playing in his room and calls me to come... I walk in to see a puddle of pee in front of his bookshelf, right in the corner. I give him the "Accidents happen, Mommy will change your underwear and next time we'll just go to the potty." Pair of boxers number two. I walk into his room just in time to catch him back in his corner, relieving his bladder again. I say the same schpeel. boxers number three. This time I offer to bring his potty right into his room, he agrees so I set it up right in his pee place. Third time's a charm. He makes it to the potty and when he's done I offer to let him empty the pot and clean it out. If there's anything that responds well to Bulldozer it's cleaning! He has a great dumping the pee out in the toilet, putting soap into the pot and then rinsing it out with water. After setting the potty back up I drag my butt to do laundry again. Not even five minutes later... "MOMMY, MOMMY, MOMMY, I DO IT!" I run into the room and Bulldozer's peed the equivalent to two drops of pee. He picks up the pot and it's off to the bathroom to complete the whole cleaning ritual again! This happened another two times (peeing drops into the potty) until he peed himself and then wanted to wear a diaper again. I'm wondering ... how does one child have so much pee in him?