If you kink the tubing you can repair it by straightening out the kink and heating it with a heat gun or hair dryer until it reforms. Be sure to hold tubing  straight until it cools. Before performing this method, practice on a scrap.
    SPLICING; extra brass couplings should  be kept on hand in case the tubing is damaged. Be sure to cut the tubing square and insert it all the way into the fitting. If the coupling is put in concrete, sleeves are should be used to protect it from the concrete. Do not leave electrical tape on tubing. 

The best pex fitting is the brass inserts with the Stainless Steel Clamps and the Cinch Tool

The brass insert fittings with the SS crimp rings are the best and can be used underground and in a slab.
They are also reusable.

We are seeing some failures with the new Sharkbite fittings, do not use them in a place they can not be accessed.  They are expensive, reusable, need no tools, and do not restrict flow.

USING BRASS COUPLING WITH BLACK CRIMP RING

INSERTS ARE REUSABLE

CAN NOT BE USED UNDERGROUND OR IN CONCRETE.

PLACE CRIMP RING OVER END OF TUBING,  PUSH INSERT INTO TUBING, CRIMP RING WITH CRIMPING TOOL ONCE

COPPER COLORED CRIMP RING IS FOR POLYBUTYLENE BLACK IS FOR PEX