Derogatory term for skim milk.  The lack of fat in the milk makes it appear watery and blue-tinged in color.
My doctor recently put me on a diet that includes reducing my dairy intake.  I've been drinking whole milk all my life and can't stand the taste of that disgusting, watery blue john.
by D Mitchell June 17, 2007
 Get the blue johnmug.
Get the blue johnmug. A sexual move, were one takes a sip of a blue slushy and spits it out into his or her partners vagina and/or butthole, providing an excelent cool sensation.
Cameron: Dude, I just gave Blair a blue john, she came instantly
Max: Yeah, that's typically a crowd pleaser. I bet her vagina was all blue after words.
Max: Yeah, that's typically a crowd pleaser. I bet her vagina was all blue after words.
by J.T. Falls September 9, 2011
 Get the Blue Johnmug.
Get the Blue Johnmug. Titty milk The thin, watery but TASTY milk squeezed or sucked out of the tit / boob / breast of a lactating woman.
by lawdad August 5, 2010
 Get the Blue Johnmug.
Get the Blue Johnmug.