We had some build a nest inside of a cushion on the porch chair that must have has a little split in it in order from them to get in there. My wife saw the cushion looked weird and when she flipped the cushion, they went berserk, she got stung. So, I figured I'd wait til nighttime to spray them, but my nosey dog had other ideas and stuck her nose in the cushion, not sure how many times she got stung but she ran as fast as I've ever seen her.