A foursome. Where as 'hitting a home run' means scoring with one chick, a grand slam means four runs so four chicks.
by matt January 5, 2004
Get the grand slammug. To awake one fine morn, and verily discover one's matress resembling a ordinance survey map with a rather warm chocolate log spread all over it as well as spew on your face and pillow.
"I do not think she will want to see me again after I came home totally ringbolted and grand slammed the bed, although your mum is a bit of a dirty slapper."
by Terry Fuckwit June 24, 2004
Get the grand slammug. When you pull your penis as far back between your butt cheeks(chicken in the rough), and put it against a window to surprise someone
by Joe cock February 21, 2017
Get the Grand slammug. A highly prestigious award given to the team who finishes UNDEFEATED in the 6 nations rugby championship. In other words, NO TEAM COULD BEAT THEM, THEY WERE TOO GOOD FOR ANYONE, NO-ONE COULD MATCH THEM FOR CLASS, SKILL, FINESSE, PACE, AGILITY, PASSION AND SHEER BRILLIANCE.
by God HelpEnglandInTwickenham July 3, 2005
Get the Grand slammug. when you are heaving sex with a chick, take out a baseball bat and shove it up into her anal cavity, then pull it back out and hit the chick in the face with it.
by john May 13, 2005
Get the grand slammug. As with the other baseball references to the bases (first base, second base, and so on) the grand slam refers to having anal sex. Since it is one up from a home run (just vaginal sex), and doesn't usually happen quite as often.
by Chris11 December 24, 2007
Get the grand slammug. involved with sexual intercourse. you start off knowing that you are going to round all of the bases. As you round all of the bases, you waive to the crowd like a pro. you take your time to round all of the bases to get the full enjoyment out of the moment. Then when u get past the home base, you high five your team who are all lined up from the plate to the dug out - and the party doesnt stop there.
by ummmm.. what tha June 5, 2005
Get the grand slammug.