Turn sideways on the bed and use the headboard as leverage (by holding on to it), or have him sit on a chair and put your feet on the rungs. Or, have him put his hands on your ass and help you lift it up and down. Recognize that it takes a little practice.
One of my old gf’s started crying out of frustration the first time or two we tried it (although she was old enough and experienced enough that one would think she would have known how). So I get where you’re coming from.
Also, girls seem to like rocking back and forth. Guys like more the up and down.