(AKA NPB) When someone sneaks over to your house at 3 in the morning to put a penguin, of any sort, on your balcony using ninja skills. This is usually done to show someone that good things do happen to good people. If the penguin is accepted by the receiving person then the two become Ninja Penguin Buddies.
Dude, have you met my Ninja Penguin Buddy yet? He is totally legit.