To promote a space or void, to publicise or advertise something repeatedly. To work very hard and/or doggedly to complete a job or task.
plug (advertise) (verb)
To advertise something by talking about it a lot or praising it i.e. on the internet or radio.
An empty space or opening in the middle of something or between two things. A place to park something or postition something in which to promote.
When I'm not doing the above I'm helping to fill the world with flowers: flower delivery by Arena Flowers