If this is not the right time to sit at the table and write, it is lost forever. You could have a notebook to jot down the ideas, that would help a bit, but will never make it up for the disciplined quarter of an hour that it takes to write down a good three page worth of inspired of creative writing.
Every day I wake up with a wealth of stories. Every day I go to sleep with even more, because the daily events, and thoughts have brought some new ones: I constantly hear a dialogue, I constantly write in my imagination. Those stories have different publics, sometimes I write for a particular person or group of persons, sometimes I write in my own language and sometimes I write in English. (I seldom write in another language to be perfectly honest, I would certainly not be able).
So how come those stories never get written down? Truth is they do. They often get written down by someone else. I realize that I can’t be writing at the speed of my thoughts, but those stories do have a life of their own, even outside of my head. This is why I love reading so much: in search of the story that evades from my mind and found its way through someone else’s, who had the discipline and the talent to write it down and get it published.