Proud Mummy Moment

Hi everyone!
Well earlier today I was stressing that Jack wasn't understanding the concept of using a potty.
I had been searching in internet for alternatives and seats which I could put on the toilet. I decided to buy a ThermoBaby Kiddyloo. A bargin at only £19.99! It's a seat which attaches to the toilet and has a step to allow him to climb on when he needs to go.

ThermoBaby Kiddyloo from www.samueljohnston.com

While we were shopping in Tesco's this evening; I asked Jack if he wanted Mummy to buy nappies. He said no. We discussed wearing "big boy knickers" (as I called the pull up pants "big boy pants") He seemed to like the idea and started saying he was going to be a big strong brave boy!
This evening when I was getting him ready for bed I asked if he wanted to wear "big boy knickers" to bed and he agreed. I asked him to try have a wee on the potty before he went to bed. To my surprise he pulled down his "knickers" and did a wee! I praised him lots and told him he was such a clever boy. I also explained he needed to tell Mummy in the morning when he needed a wee.
I hope he continues to enjoy using the potty and toilet seat when it arrives.
Any advice on how I can keep up using the potty? I didn't want to start bribing him with anything. Maybe I could reward him with a sticker chart or something?