Do either you or he own a wand type vibrator? If either of you do, there is an attachment called the "Humming Bird". Well, at least I've seen it other places with that name.
The way it works is, he would slide his penis into it, lubed up of course, and he can adjust exactly where he feels the vibrations. This way, it doesn't have to target the penis head unless thats what he wants.
Eden actually is currently running a promotion on both the wand and the attachment should you need a wand. You can find both the attachment and promotion here, link