Send it! Give it up!
What makes the phrase sometimes funny/abrasive is the implied 100% ownership of "it" (i.e., come to papa).
Often implies a diminutive order (Send it, sucka!) to immediately send/give whatever "it" is to the speaker (Dat's ALL mine; hand it over!) and it is usually said in a self-congratulatory tone (I am awesome, it is awesome, thus it is mine; ship it).
Poker usage: "Ship it" conveys a confident and impatient 100% ownership of the money in the pot. Saying "ship it" with a mediocre-but-still-winning poker hand usually gets a laugh, especially if you say "Ship it" after showing your weak hand but before you see the other person's weaker hand. It also usually gets a laugh if you say "Ship it" when the pot is tiny and uncontested... ship it, ship it all.
My pocket aces beats your pair. Ship it, fish!
You look nice in them jeans. Ship it.
You've got the answer-key???? Ship it.
Everyone folds to me in the big blind??? Ship it.
Said at Foxwoods, before taking down a $1400 pot against an expected low (busted) flush draw: "Queen high. Ship it!"