Deriving from a gaelic word for 20 "scór",
a scorebag refers to a bag of weed worth 20 euro/punt.
It may also be used in a variety of ways as an insult (generally for a male) ie. someone who is cheap, someone who takes drugs ( a junkie ), someone of low socio-economic status , a bogie and more ..
Scorebags is an exclamation of success and joy. It is used in similar situations as "Woopee" but is not nearly as camp.
It is also significantly easier to use in a sarcasticfashion compared with "Woopee" (which still just sounds camp).
Person 1: "You just won the lottery with a ticket that you found stuck in the thong belonging to the supermodel you took home last night"
Person 2: "scorebags"
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"