How to give a good Handjob

Kelley
So, sometimes, we can't have sex. Whether it's the place, or time or whatever, no sex. So we instead just touch each other, he fingers me, I give him A handjob. He's great at fingering but I can NEVER make him cum. And if I do, it takes like 10 minutes and my arm wears out, and I feel bad cause I'm satisfied but he's still hanging out not getting any. 
HOW DO I GIVE HIM A GOOD HANDJOB?! I think that after a while, he thinks I'm just doing it to please him (I mean, I kind of am) and that I don't really want to, but honestly I love it when he orgasms, and I wanna get it done like he does for me. So HALP