88th base Share definition Flag when one man drinks the semen of another out of the anus of a woman who is performing fellatio on the man who is drinking the semen. Man 1: Dude, I went to 88th base last night.Man 2: And I with your mother! 88th base by Gfalz November 6, 2010 0 0 Get merch Get the 88th base mug. Buy Now — $32.95 See more merch