Yost Cheer Quesion - Woop woop?

Let me start by saying I am not a noob to Yost, I've attended every home game for several years. There is one cheer that I am confused by and still don't necessarily understand the significance of - that is when some students go "woop, woop, woop..." as the other team brings the puck up the ice (generally during their power play). Brian mentioned this at one point (complaining about the misuse) but I haven't been able to find the post. Can anyone clarify?