For me, I sort of imagine the sensation of eating something and observe how I react to it. If it's a strong positive reaction, that's what I'm in the mood for. Otherwise, if it's kind of a more bored reaction, I cast my mind out for another idea and try again.
Because the interior version is strictly inferior to the real thing, at least for me. It's, maybe, 80% as good, but that last 20% is a real humdinger.
Especially for music, I have a hard time hearing it in my head and not playing/singing/drumming along with it. Currently working on "Winds of Change" by the Scorpions as practice, and it's basically been playing in my head for the last 72 hours.
I do have to listen to it occasionally to refresh, but it certainly makes learning music easier... if not infuriating. Looking at you Lou Bega, and Rob Thomas.
Does 80% mean "tastes like a dull chocolate bar, but still basically a chocolate bar", or more like "like a nice chocolate bar but somehow 20% less enjoyable in some looser way"?
Perhaps this is why I can't identify the beat in the music.