do a Reggie Perrin means: To fake one's own suicide.. It is informal slang, fine in casual speech but not suited to formal contexts. It touches on mental-health themes; if your teen uses it about themselves, a calm, non-judgemental check-in is worthwhile rather than a confrontation about the word itself. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.