The expression wanh wanh was created by two girls in oakville from Holy Trinity. It is derived from the tune commonly heard when something goes wrong *wanh wanh waaawaawaawaannhh*. It is used when someone lets you down.
-"no guys i can't do that i'm too scared.."
-"oh my god, don't be such a wanh wanh"
-"sorry, i can't make it to your party"
-"ok but just to let you know everyone is going to think you are a wanh wanh.."