A fork of Rural Dictionary
When your buddies bring home a grenade and their vision might be cloudy due to inebriation, you can help them by grabbing a 'vuvuzela' and blowing loudly enough so that your buddy hears it and realizes that they are with a grenade.
"Wow Billy brought home a grenade, I have to help him out. (grabs vuvuzela and blows into it). Grenade Whistle!!!"
Billy: (hears vuvuzela) Oh Man Grenade!!!! Abort!!