1. a sexual act performed when a female is spanked with a baseball bat before it is pushed up the partners vagina.
2. when a partner of any gender is spanked with a baseball bat before it is put up the partners ass hole.
3. the repetitive grand slam: after the spank the baseball bat is repetitively placed up the vagina then ass of the partner, or, if preferred, two bats at once in both holes.
Carol: Tiffany, why are you walking funny?
Tiffany: I got the most intense east coast grand slam last night...
by YOUR FRIEND TRIN <3 February 20, 2015
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