69th base Share definition Flag The nirvana of sex. One gains entry into this spritual place after giving sixty-nine different girls a 69er. "Dude, what's 69th base?!" - Dominik "That's where I got last night biatch!" - Ramesh 69th base by Rameshdogg September 18, 2008 0 0 Get merch Get the 69th base mug. Buy Now — $32.95 See more merch