In computer software - it means to publish / distribute the application in its current state. Often used humurously when the software is buggy and clearly not ready to publish.
1) The affirmation of a suggested act of extreme awesomeness 2)OR a reinforcement of the awesomeness that has occured in the past.
3)OR the act of giving someone something awesome.
Dude1: Let's go get drunk with these hot chicks?
Dude2: Ship it.
Dude1: Did you score with that hot chick last night?
Dude2: Consider it shipped.
Dude1: You were wasted last night.
Dude2: Yeah, that cocktail waitress shipped me seven jaeger bombs.
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.
When you ship two characters (typically from cartoons/anime) so hard that you have to mention the shipping service, fedex to add extra emphasis on the pair you are shipping.
-person is watching something with a friend-
Person1:"Whoa! that was good, especially the part with frank and tina!"
Person2:"Yeah I totally ship it."
Person1:"really?"
Person2:"Yeah manI ship it like fedex!"