Luckily reaching a women's G-spot doesn't require contorting your bodies into pretzel-like positions.
The woman-on-top and doggie-style positions are two of the best positions to reach a women's G-Spot
With the woman-on-top position women should face the man and lean back slightly, raising their pelvis and supporting their weight with their hands. The woman can slide up and down on the man with slow, steady strokes. This position allows women to shift themselves around to stimulate their g-spot.
Using the doggie-style position will allow the man to aim his penis with the help from the women towards the G-Spot. He can then apply rhythmic pressure in this area to stimulate the women's G-Spot
The basic missionary position doesn't rate all that high on it's ability to stimulate the G-spot, unless you place a pillow or two under the women's lower back. That raises her pelvis up a few inches so the man's penis can more easily rub against the women's g-spot.