IWTOYWIM Share definition Flag Stands for "I will think of you when I masturbate", A creepy message to put in the back of your classmates yearbooks. "Julie, HAGS! See you next year! IWTOYWIM!" IWTOYWIM by Urban Dictionary January 26, 2009 0 0 Get merch Get the IWTOYWIM mug. Buy Now — $32.95 See more merch