Huachi Enema

Anybody tried using this on their toddlers with constipation? My child is 20 months old. Mine is afraid to push the poo out probably due to a traumatic incident involving pain when pushing out large poo. My child eats fruits every alternate days however does not like to drink plain water. I've tried all means to get him to drink more water and assist him to poo comfortably but to no avail.