The anus.  Yin in Chinese philosophy refers to feminine energy, while yang refers to masculine energy.  The word has been incorporated into American slang to mean the male/female part.  In effect, while males and females have different sexual organs, the anus is common to both sexes, thus the use of yin(female), and yang(male), to denote the anus in sexual contexts.  Infrequently used.
by tortfeasor January 12, 2006
Get the yin yangmug. by mr.bruce November 16, 2010
Get the yin-yangmug. by Digitals December 9, 2008
Get the yin-yangmug. by deeznuts2475 August 3, 2012
Get the Yin Yangmug. Let's yin-yang our company by reducing the number of male staff and increasing that of female staff.
by uttam maharjan November 23, 2010
Get the yin-yangmug. The sexual act of 69’ing except exclusive to when Tyler Hojnoski (Caucasian) and John Hall (African-American) 69 thus creating a yin-yang.
by Bomb 0mb August 24, 2018
Get the Yin-yangingmug. 