DS's treat was wearing his "big boy" undies. He was so proud to be wearing them. He caught on really quick so we had very few accidents. We had a few no 2 accidents though so the first two times he did his no 2's on the toilet, we gave him matchbox cars. But as a reward, not a bribe. As in, we didn't tell him beforehand that he would get one. I was so happy he did it, I gave him a special treat. We just gave heaps of praise and encouragement mostly.