Hmm. For me, when I had small children, what would have worked would be to have a “secret” storytime setup for him. House kind of squared away, recruit the kids to set up a place to put their Dad in the center of, and have them recruited to read a story.
The “secret” part might be you kneeling at his feet “playing along with” being one of the kids. It would be platonic rather than naughty, but for me it would have been lovely to get to be both their dad and your Daddy.