In the act of masturbating to online pornography, when your hand reaches the top of your shaft and slams the desk and creates a thunder-like sound.
person 1: Is it storming outside? I hear thunder but I don't see any lightning.
person 2: Oh that's just John in the next room over thunder fapping. He must be watching some good stuff.
person 2: Oh that's just John in the next room over thunder fapping. He must be watching some good stuff.
by Spilner May 05, 2011
Get the Thunder Fapmug. by pimpassnigga September 11, 2012
Get the Thunder Fapmug.