I had that happen to me before. I've found that if i tease my dick more rather than just plain pumpin it up and down, i "squirt" more wen i cum.
When i say tease it more, i mean rubbing and stroke the head of my penis where i'm more sensitive and playing with my balls, lightly stroking my dick and stuff. Even get a bit of lube going... just experiment dude.
I find doing that and trying to hold it back as long as i can feels awsome and works...