A vag volcano is when a woman squirts out of their vagina during an orgasm. Only 13% of the female population are able to squirt. It is called a vag volcano referring to the liquid shooting out of the vagina, which simulates lava shooting out of a volcano
"When I was fucking that girl she had a vag volcano and the liquid got all over me!"
by MMHvagvolcano April 15, 2009