I usually try to replace the word "gay" with "lame", particularly after a story my friend told me.
He said how he was at work one day and he let slip the phrase "that's gay" while a homosexual man was walking behind him. He called him out saying "That's not gay, that's lame. I'm gay."
So he started saying "that's lame", to which I made a joke at his expense every time he says that. I have a physical handicap that makes it difficult for me to walk, so any time he says "that's lame", I say "That's not lame, that's gay. I'm lame."