To do a Bucky is to adopt a false persona in order to conceal one's homosexuality. Named after the fictitious, gay cowboy H. C. G. J. Bucky who believed that raising a ruckus would divert attention from his true nature.
That chap in the stetson keeps talking about hookers and blow. Is he demented?
No, he's just doing a Bucky. He's really as gay as a party frock.