kiddin'

It's just like kidding, only cooler.

You suck, I'm just kiddin' bro.

Kiddining

The word kidding, just with an extra -ing on the end to make it sound cooler.

Your stupid, LOL just kiddining!

j kiddin

means just kidding. other way to say just kiddin. Used at the end of a sentence to make it completely void, therefore contributing nothing to the conversation and wasting everyone's time.

Nikki- I f@#king hate your guts!!!!
Me- WTF?!?
Nikki- J kiddin!!!