feck is just a version of "fuck", all of Ireland says it constantly, and for some reason I don't understand, its not considered as rude as saying "fuck".
whopper is very good, or big, and it is synonymous with "massive", which we also say a lot, like so "dat breakfast roll was massive".
And people in Dublin frequently slip "only" in to phrases for emphasis, "dats only massive" "you're only gorgeous" "you're only brilliant". I'd say women say it more than men do....
Its hard to imagine I'd say, without the accent