Toilet trained

I have a 5 year old son who is fully toilet trained but sometimes he gets soo involved in playing that he doesn’t want to go, even though i see him ‘holding and dancing’. Or he ends up running at the very last second. And ends up having accidents. We tell him to go and he says it’s boring. We remind him he is a big boy and needs to pee in toilet. We have been nice and firm but still he keeps having pee accidents every few days.

Is this normal behavior? What should i do. How do i train him more. He still is not night trained. I feel i have done something wrong hence he is like this. I don’t know what to do.