NSFW -- "Letting go" for a g-spot orgasm (see details inside)

When I’m with my partner and my partner is penetrating me using the curled fingers motion, I have a hard time letting go when it comes to a g-spot orgasm. I feel the build (feel as though I have to pee) and it’s really intense. So much so, that I can’t let go (allowing myself to cum) and I usually have to stop.

Any tips for getting over this? I really want to get over this.