Quoting Noah && Libbys Mommy :" I was meaning like laying next to one another or kissing while you do it. It was just a thought but idt my SO would do it. Id be nervous but id get over it."
oh, we've done that, don't ask just kinda start doing it, well, do it to eachother then just guide his hand back to himself and he'll probably get what you want him to do.
Or, strip, sit in front of him, start masturbating and forbid him to touch you and refuse to touch him, I bet he won't be able to handle that for long before he starts touching himself