I'd probaly sit down, enjoy the soft feeling and fall asleep. I always wondered, if there are so many worlds (I suppose there are many, the books says there are many pools), why aren't there more people snooring next to a tree? I mean, I don't think it's likely that uncle Andrew is the first to find a way to other worlds, and if Digory and Polly weren't together, I think they would have stayed there forever. It doesn't seem like a world where it's easy to die, but maybe you can starve there? Or maybe forgetting who you are isn't as likely as it seems, so the ones who get there also get out.
If, by any chance, I don't fall asleep, I'd wait a while and see what happens. If peaceful creatures from other worlds appear, I'd follow them, but if that's not the case, I'd go back to my own world. I'd be too scary to enter something like Charn.