When I'm writing a novel I never, ever go to bed without a pen, maybe two, in my bed. (Yes, I sleep alone, thank you!)
Where the other person is supposed to be I have several books that I'm reading, all with envelopes as book markers. On these I write the ideas that come to me.
And most important, I get almost every single idea worth writing while lying down. Furthermore, if it's a plot thing I'm searching for, I lay on the right side so the blood sits in that half of my brain. Emotional scene, left side. Erotic scene, shower.
Hey, maybe I should get a life!