Okay for this you need 4 gentlemen and a chick. A party may be a good place for this. The first three gentlemen need to make out with the chick. They each get to "first base." The bases are loaded as the "runners" advance. Finally the fourth gentleman approaches the chick and proceeds to have sexual intercourse with her. Once he "gets all around the bases" by this act he has "hit a grand slam home run." Or simply a "grand slam." The remaining gentlemen burst into the room and many hi-fives are exchanged while they all yell, "Grand Slam."
Hey I hit a Grand Slam with this chick and some help from my best buds last night.
DP, or short for Dynamic Programming (not to be confused with Double Penetration) is a methodology for solving complex problems by breaking them down to overlapping sub-problems. In most cases, DP problems are hard to solve by yourself, so learning DP with friends is extremely recommended -- in which case you may as well begin practicing the other DP variant as well.
My friends and I got stuck trying to solve this DP problem, so we just ended up DP'ing this girl instead.