Alternatives to saying 'boy' or 'son' during sex?

I recently started hooking up with a younger guy (only about 15 years younger) who likes to call me Daddy. I don't mind, but I'm having trouble figuring out what to call him that we'd both like (boy is out for both of us, son doesn't feel right). Any suggestions?

I know I can call him by his name, but I'm trying to have some fun with being a 'daddy'.