I once heard a story (don't know if it's true or not) about a professional piano player who went to prison for several years. After he was released, he was supposedly playing better than he was before, in spite of the hiatus. When asked how, he said he simply visualized himself playing. Now, I'm NOT saying this is a substitute for actual practice, because nothing is, but I've recently tried something similar and I HAVE found it to work (for those moments when you're away from the instrument) If a song or melody or whatnot pops into your head, or if you hear a song on the radio, try to visualize the proper notes being played on bass. It's a bit tricky at first, but as I said, I've only been doing this a short time, and I've noticed a difference already. I find that picturing the fingerboard of the bass helps to focus your attention on figuring the song out. Any thoughts on this?