J.S.
My mom has been an elementary teacher for 30+ years . She in here classroom ( bathroom in the class) told me to use the cheap fruit loop cereal. The boys grab some in their hand toss them in the toilet and fire away. The fruit loops will go down and then pop back up. My son loved them. We did the same thing with him and he never had an accident. They also don't clog. I kept some in a container under the sink so he could grab a handful when he needed to. I also carried some in a zip loc when we were out and about. Worked great and cheap!
J.