Canadian insult, nothing to do with hockey. As any young boy can tell you, the resemblance between a penis and a hose is obvious. Therefore anyone who is a "hoser" pisses on people, figuratively speaking
(Canayjan): "We all ponied up to buy a two-four, but Kyle deked off, and drank it himself. That hoser sure hosed us. What a hosebag." (Trans.): "We all chipped in to buy a case of beer, but Kyle stole it and drank it all by himself. That prick sure screwed us over. What a bastard."