Definition of ship it
If a player is very happy to win a big prize pool, you may hear a shout of joy as he says "ship it!". There is no exact way to translate this expression into English, but let's risk this one: "Par ici l'argent (ou les jetons)" or, "envoyer-moi l'argent"! ship it is an expression used in poker tournaments. You will almost never hear this expression in the game of cash game. You can also shout "ship it" when you are satisfied with a game. If we call a big bluff and our opponent folds, the jackpot will be sent to us and we could yell "ship it"!
Getting cocky at the poker table
Shouting "ship it" is also a way of imposing it. You can shout "ship it" because you're happy to win a jackpot, but you may also want to impose, as in the example above of bluffing. If you call a big bluff AND show your bluff AND yell "ship it", let's just say that it might upset your opponent a little bit. On the other hand, it might intimidate him because you'll look like you're in complete control of the situation.