How do I get more sperm to come out of my penis?

This is a hugely embarrassing question but I've seen men ejaculate an ungodly amount of sperm and I usually do about a palm full or less. I was just wondering how do I get that much sperm to come out of me? Is there a pill or some medicine that makes it happen or does it depend on the person, like everyone different? I'm wondering how this happens more than wanting to do it that's all.