For me, if the male doesn't want to mount and hump mostly on their own after foreplay, they often have already played, aren't feeling well or in the mood, or have been too used to being masturbated. They gotta be into it or we just wait till next time.
A female dog is not a human.
For example dogs that are used to be jerked off, may learn to not put any effort into it when you literally do all the work for them.
I mean, all dogs are different so I imagine people will have trouble giving any exact advice. But... I managed it in the same way I teach my dog anything, just be gentle and don't get frustrated if it takes a while. If anything it's easier to train than most other things cause it comes with it's own reward.