For me, I have multiple ways I can cum and it all depends on how I'm stimulated. For the biggest load and most powerful orgasm, it takes a while, but its by not directly touching the head of my cock. Pulling the skin gently down my shaft until it lightly pulls down on the underside of my head.
It takes a while, but during this process I am incredibly hard the whole time, my cock is just throbbing and when its time to cum it's definitely the thickest and most number of ropes I can shoot.