1.) A name which a man gives to his penis when dissociating himself from responsibility for its actions or reactions.
2.) A homosexual character in jokes which heterosexual people make about homosexuals. There's usually another homosexual (called Cyril) in the jokes.
1.) "It's not me doing that, it's Percy."
2.) "Cyril and Percy walk into a bar. Percy says, "Thyril, is that a gun in your pocket, or...?'" (followed by the rest of a lame joke).