I am getting ready for back to school and was going to order another pump case for my four year old. He usually wears a small baseball style pack around his waist from Pumptastic. I just saw a waistband advertised on another website. You put your pump in the waistband and wear it under your shirt around your waist. This seems like it would be more out of the way - a good thing. Has anyone tried a waist band for holding a pump? Comments? Not sure if this would work for a 4 year old.