It's Raining!

Until today Aiden was doing great with the potty training. I told someone that potty training him has been a non-event. Aiden decided on his own that he was ready to start wearing "daddy underwear" and until this morning he has only had two accidents, both outside. I expect some accidents while potty training but today was no accident! First, he peed on the carpet in our room (ok, this probably was an accident). However, 10 minutes later Aiden decided it would be fun to stand at the top of the stairs and see how far he could pee down the stairs, laughing all the while. I would like to say that I remained calm and explained to him that this is not where we pee but that was definitely not the case! I called Rick and said "Guess, what your son did?". He assured me that he did not teach him how to do that. I would just like to know where he got the idea to do such a thing?