A spoonerism for "ugly sisters." Originally referring to the characters in Cinderella, this fun little phrase can be brought out whenever you have to refer to a friend or loved one's less than charming female siblings.
1. (usage for a lover) "Oh Crap, I promised Bob I'd spend Christmas with him, but I didn't realize his Sisty Uglers would be there too."
2. (Usage for a friend) "Jane, you know I think you're awesome, but your effin Sisty Uglers always give me attitude."