straighten up and fly right

If someone tells you to straighten up and fly right, they mean to say you should improve your behavior or attitude and begin performing better. This phrase is originally referring to an airplane that needs to fly right, as in straight rather than all over the place. Figuratively, this means you should stop messing around with frivolous, unimportant things and begin behaving and acting appropriately. You might be behaving badly or simply inappropriate for the given situation.