Three Day Schlong Share definition Flag A penis that is so large it takes 3 days to completely penetrate a woman during sex The reason I was gone all weekend was because I was having sex with Chris and he has a Three Day Schlong! Three Day Schlong by Dr. Gray October 7, 2011 0 0 Get merch Get the Three Day Schlong mug. Buy Now — $32.95 See more merch