I had one of these when I used to hang out in Detroit. Would take it out and play with it any time I felt some nog was about to try to fuck around on me. Like this one time I was just sitting on the curb near Plymouth and Evergreen, hanging out waiting for someone, and this nog was also sitting there with me. Noticed every time I looked away from him and looked back again, he was a little closer. Took out the butterfly and started playing with it. Fucker got up and walked away. Never actually had to use it on anyone.