your friends awkward, often creepy and more times than not, inapropiate boyfriend.
It's not that these gentlemen are intolerable individually but when with a large number of their
girlfriends girlfriends, their "manshadow" qualities are more pronounced. Often the manshadow will only talk to/address significent other, giving him a more hollow persona, hence shadow. Usually uninvited.
(Linguistic credit goes to Alex)