When I came out (to my mother), it went quite well. For whatever reason my little sister wanted to do a “costume party,” so I dressed up in rainbow and put some paper saying “I’m bi” on my shirt. Then I went into my closet and ran out, saying, “I’m out of the closet!”
She needed about ten seconds to process what I was doing but was very supportive, which isn’t surprising because she’s very liberal and open-minded.