1 definition by Smitty bros

When a guy inserts his penis into a vagina and pisses. While the female simultaneously urinates. Hence, causing a massive vaginal geiser of urine.
Man, can you believe that Sarah let my brother Allen give her a Gadsden Geiser. It was so messy, his bed looked like a swimming pool.
by Smitty bros January 03, 2020
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