I believe that God was fucking with you when he put your g-spot juuuuust out of reach of your fingers. Or maybe it was just his encouragement to get someone else involved, as it’s the perfect distance for someone else to reach in and rub.
Either way, my point is it’s really hard to make yourself cum from vaginal stimulation from your own fingers. Even if you do manage it you’ll probably get such cramp in your hand you’ll wish you’d never heard of masturbation.
There are two easy answer though. One is toys, two is use somebody else’s hand.
Assuming the latter isn’t available (and please don’t do it without asking, humping a stranger’s hand without permission is illegal everywhere but Ohio) then you’re left with needing to use a dildo. Even better, with a suction cup dildo you don’t even need to use your hands, so you can use them for things like nipples and stopping your face hitting the ground.
If you don’t have a dildo check out my DIY Sex Toy suggestions – your g-spot will thank you for it!