rusty iguana

This is when you are banging a girl on the beach and you pull your slong out of her, then proceed to get sand stuck to your penis. Once your penis is fully coated in a layer of course sand you then forcefully penetrate you womans anal canal whilst she remains unaware. Due to the sudden shock of a sandy peen in her butt she will thrust her head forward poking her tongue out much like an iguana's reaction when scared.

Bro I gave Sandy such a Rusty Iguana last week, she's still getting grains out as she poops.