It means you are about to do something, or more accurately you are doing something now that will lead to you doing the thing that you are fixin' to do. Fixing = preparation
Others here have the pronunciation wrong, when spoken it sounds like one word: "fixina" which led to it's child word finna
In the South we like to run our words together, it's too hot to pronounce every letter.
Texan: "I'm fixing to go unload my pickup cuz it's full of junk and I've gotta go get cokes for the party."
Translation: I am in the process of preparing to go begin unloading the miscellaneous items from the back of my truck because I must go purchase beverages for the party.
I am fixing to take my shower. Anyone need in the bathroom before i do?
or
Dude, watch this, Rocky is fixing to kick Appollo Creed's ass.
or
Im fixing to go out , so don't wait up for me.
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the USCoast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.
I had a trucker's tan after driving for 10 straight hours on a sunny day.