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SDBF is an acronym for Super Duper Best Friend. Being someone's SDBF is the highest level of friendship possible by two members of the human species.
"You want to take our relationship to the next level"
"Helz yeah! You should be my SDBF!! "
"Yes! I've always wanted to have a SDBF! "
by Velociraptorsunited February 21, 2012