If it were me I'd probably soak him just to help, but others may say to wait and that he'll do it when ready. After two feedings if I haven't noticed anything and it's on the third feeding, I'll soak them just it's what has always worked for me. I normally check on the two days prior to feeding to make sure. Then that way I know if I'm doing cage maintenance ahead of time, though there is the occasional unsuspecting mess to find on feeding day.