I do not care what you say or think “If it's at all possible, I'll do it, you know I will.” “Oh, Rob, up yours. Just do it, if you're going to, or else stop talking about it.”
A vulgar exclamation of contempt, as in So you think you can beat me? Well, up yours! This expression, a shortening of the even more vulgar stick it up your ass, is sometimes accompanied by an obscene gesture (see give the finger). [ Vulgar slang; mid-1900s]