To keep ones options open. Like a bird flying along the coastline, neither heading inland or out to sea, refraining from making a decision at the present time.
Generally refers to a current indecision about where to party that night when given two possible options.
Used most commonly in New Zeland where birds can be seen loitering around the coastline, often a common location for bars/clubs.
"hey where are you heading out tonight? (Insert name here)'s party or clubbing downtown?"
"hmm, im still coastal at the moment."
OR "im keeping it coastal." (when pressured to make a decision)