What is Filthy Gecko?
1.
when you are fuckin a girl from behind, up against a wall, you take your penis out of her vagina and stick it in her bumhole. Then you hold her down as she struggles to get away, which will look like shes trying to climb up the wall.
Joe : hey man i gave karen a filthy gecko last night!
Bob : HAHA yes (high fives Joe)
See