The act of rapidly assualting your sexual partner with your testicals, usually during a very rough period of sexual activity.
Sue : Hey Carrie, what happened to your face!?!
Carrie : Just between you and me, Bill gave me a Genital-Thunderstorm when I wasn't expecting it last night.
Sue : You have to watch out for those!
Carrie : Just between you and me, Bill gave me a Genital-Thunderstorm when I wasn't expecting it last night.
Sue : You have to watch out for those!
by Thoriail July 31, 2013
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