A fictional abulance or rescue squad for someone who cries or whines, most often without provication. A way to insult someone whom often cries for no apparent reason; a cry baby, a brat, or someone suffering from hypochondria.
" Waaa, waaa, I want a cookie waaaa, waaaa, waaaa!"
"Did someone call the wambulance, WAAA! WAAA! WAAA!"