NEVER, ever, use any oil on any telescopic baton, it will never close properly.
It may take a sharp downward thrust to close the baton, but usually gets easier as the baton is used.
Its easiest to close the baton on a hard surface like concrete. You should use a piece of card board or mat to avoid abrading the tip, but that is up to you.
The harder the surface, the easier it will close when the baton is new. After awhile you can close on other surfaces without an issue. Be aware you may mar the surface you are closing the baton on.