Literally, an all-male gang bang. In the context of a party, however, mang bang is similar to a sausage fest, though it is comprised of closer friends. The main difference between a mang bang and a sausage fest is that the hetero-male participants in a mang bang are usually clueless as to how homoerotic they appear.
"Damn, that was such a mang bang I totally didn't realize no chicks were there."
af Ross Sewage 26. oktober 2006