Stop the presses!!

I cannot believe what has happened today!
Alex has pee'd in the toilet. Three times!!
Before today, he would climb onto the toilet and sit for a half a minute or more then declare he was done. Many times, he would go pee on a carpet somewhere before I had the chance to get him back into a diaper.
This morning, however, he took his own diaper off and tried to pee on his brother. Thats right. He wasn't able to make himself go on the toilet, but he could make himself go on his brother. Lovely. So I quickly grabbed him up and set his little bum on the toilet - and he went! I made a huge deal so he would know that was exactly what was supposed to happen. Ajay heard the commotion and came in to give Alex high praises, too. I told him he could get a sticker for such great work. He was excited about that!
He hopped off the toilet and went to play in Ajay's room - where he started peeing on the carpet. So, again, I grabbed him and put him back on the throne, and he was able to go again. Our prince could now get TWO stickers - plus a call to Daddy at work to brag about his successes.
Flash forward to this afternoon. After nap, the boys were pretending to camp. Alex came out of his bedroom clad only in a shirt. I marched him back into his room to get a diaper on and asked if he wanted to earn another sticker. He told me no. So I asked if he just wanted to use the toilet without the sticker, and he said he did (I guess he's got a two sticker limit).
So up he climbed and went (I could tell he was forcing it out, not relaxing and letting it all go). Again, I did the clap-happy-pee-dance and Ajay came running in to clap along with me. Three times in one sit, he went. Now we just need to get him to figure out how to relax instead of forcing.
He's in underwear (the thick kind that is a bit more absorbent than his Wiggles underwear). I've got the timer set to 30 minutes so we can go back and try again. This is a completely different technique than I used for Ajay - but hey, whatever works!!
Wish us luck!