A vaginal secretion of air (queef) of unfathomable magnitude. It is of too low of a frequency for human ears to hear, however it has been felt on a handful of occasions. The only known members of the animal kingdom known to be able hear muff thunder are Humpback Whales. Further research is being done as we speak
No, I was having really intense sex with Cindy and she let out some ridiculous muff thunder and rumbled my lamp off of the nightstand and it fell right on Simba's head.
by JKallday April 28, 2011
Get the Muff Thundermug. by trollson November 12, 2008
Get the Muff Tinglermug. A woman who has such a hairy pussy that through tight cotton spandex it appears that she may have a cock and balls.
by AD218 August 28, 2008
Get the Clumper Muffmug. "Every well dressed woman at the end of the nineteenth century would have had a muff, to keep her hands warm in during the winter, and she'd have used her muff brush to give her little muff a little dusting over." Tim Wonnacott, BBC Bargain Hunt, Series 26 Episode 8 Derby, 19 May 2010.
by Mustn't Grumble May 30, 2011
Get the muff brushmug. by Hairy McDude January 8, 2004
Get the Furry Muffmug. 
by nevsky September 12, 2006
Get the beaver muffmug.