“The Rule of Thumb” – Women who have less than 2.5 cm (or, the distance from the tip of a thumb to the knuckle) between their clitoris and their vaginal opening are more likely to orgasm from penetration alone.
Only about 25% of women are able to orgasm through vaginal penetration. The Rule of Thumb suggests that this is because of physiology, not psychology! The closer a woman’s clitoris is to her vaginal opening, the more stimulation it receives through penetration. So, neither vaginal nor clitoral orgasms are superior to one another, as a vaginal orgasm is really mostly a clitoral orgasm through a different kind of stimulation!