Comforting a Grieving Child. Their diaper stays dry for about two hours at a time during the day. Follow these simple tips and you should be crossing diapers off your shopping list in no time: These steps may help him stay dry through the night, and let you both say 3 year old peeing and pooping on floor to the nighttime diaper. Nov 25, Amber Bobnar. Your child will show you tell-tale signs that they are ready. These pants are more absorbent than regular underwear and can pick up little leaks. You can pair them with vinyl pants as a nice in between stage between diapers and underwear.