The Hegh'bat was a traditional Klingon ritual suicide. According to law and ritual, when a Klingon could not stand and face his enemies as a warrior and he or she had become a burden to his family and friends, it was the time for Hegh'bat. The honor of helping the warrior would fall onto a family member, preferably the oldest son. That person's role was to hand the badly injured Klingon a knife so that he could plunge it into his heart. The family member would then remove it and wipe the blood on his sleeve.
In 2368, facing a life of paralysis, Worf asked William T. Riker to perform the ritual. Riker declined, not wishing to see Worf die. In an attempt to convince him not to give up, Riker later reminded Worf about whose role it was, surmising (correctly) that Worf would not be able to bring himself to ask Alexander to kill him. (TNG: "Ethics")