not sure what you mean with this question. Are you refering to when you have a full tank of gas and you over fill it, so it starts coming out of the filler hole? Or is it leaking from the filler neck as you are fillin her up because of loose worm clamps? Please specify?
The first few times I stopped for gas I had a problem with the fuel leaking out the filler opening. I have since adopted the fill slow routine and that seems to be working better.
The bumper and the angle of the fill tube will not allow you to fill very fast as others have said. I have thought of devising some kind of quick clamp to fit on a rubber hose that I could quickly clamp onto the gas station nozzle to allow faster fills, but I wouldn't want to carry it around in the trunk smelling like gas. I have heard someone say to turn the nozzle sideways but that didn't work very well either.
I think a lot of the problem is the new style nozzle that has the rubber boot to seal the tank opening. If it is worn, it will spill. Some are so worn, I have to hold them in with a lot of force to seal the filler neck opening.
If you use the trigger lock (that is if they are allowed in your area); never, ever let go of the nozzel to go check your oil or wash your windshield while filling.