"Shame on you" is a rather harsh thing to say to someone, as is the alternative, "You should be ashamed." It would rarely be used, except maybe by parents to their children, when pointing out misbehavior.

Hello Jju: You can phrase your meaning like so: "Your behavior is inappropriate." "Your behavior is unacceptable.". "Your behavior is reprehensible." "Your behavior fails to obtain to a moral standard." "Your behavior fails to obtain to an acceptable standard." "Your behavior is deplorable." "Your behavior is crude." "You fail to impress." Or, you can simply say;: "Shame on you."

More alternatives: You should be ashamed of yourself [Plural: You should be ashamed of yourselves.] You ought to be ashamed of yourself/yourselves.