Sir Gaywain
A change on the name Sir Gawain, seen in the popular medeival prose, Sir Gawain and the Green Knight, is an insult used to describe an effeminate man. This is generally used in close friend circles to describe short outbursts of gayness among friends.
Guy 1 - "I'm actually thinking about seeing the new 'Sex in the City' movie."
Guy 2 - *Laughs* "Alright Sir Gaywain.
Guy 2 - *Laughs* "Alright Sir Gaywain.