What you say when someone wrongfullyassumes you will be included in an undesirable activity. Another way of saying "what do you mean we?"
Holly: "I told my cousin we would help him move this weekend."
Ramon: "Got a turd in your pocket?"
Holly: "Excuse me?"
Ramon: "You said 'we' so you must be referring to yourself and the turd in your pocket. I have plans this weekend."