After he initiates each new member of Project Mayhem, Tyler Durden kisses the member’s hand and then pours lye on it, giving the member a horribly painful, kiss-shaped scar. The scar, “Tyler’s kiss,” symbolizes the “painful pleasure” of Tyler’s philosophy and his tutelage. Tyler is tough on his followers, including the Narrator, but he believes that he’s helping his followers by leading them to enlightenment: the excruciating pain of the lye is supposed to get them closer to the “real.”
While Tyler’s kiss is arguably about achieving individual enlightenment and a sense of aliveness, the fact that all of his followers receive the same mark also shows how self-contradictory Project Mayhem really is. The group is supposedly about bringing down mindless, repressive consumer culture, but in the process it becomes similarly mindless and repressive—all the members have the same mark on their very bodies, receive the same indoctrination into Tyler’s ideas, and are expected to give up their identities and lives for the “greater good.”