G**!
You may end up having to drain the dirty bathtub etc
Tip: attach it to the side of your bath tub. Then when placing your toddler in the warm bath water, keep him entertained/distracted so that he doesn't sit down. When the warm water gives him an urge to wee, deftly remove the light green insert and place it under him as he starts to tinkle. You may end up having to drain the dirty bathtub etc, but so far it has been the best way I've found to control his urge by naturally - because everyone knows how easy it is to go to the bathroom when someone is staring at you saying "go potty?" "go potty?" "go potty?...." This let's him do it on his timeline.
