Adanji is a type of Klingon incense, well known to be used in the Mauk-to'Vor ritual of suicide.
In 2267, Karel obtained adanji when he wanted his mother to perform the Mauk-to'Vor ritual on him. (TOS - Errand of Fury novel: Seeds of Rage)
Worf obtained adanji from Quark to use in Kurn's Mauk-to'Vor ritual in 2372. Jadzia Dax realized Worf's intention when she heard from Quark that Worf had obtained adanji. (DS9 episode: "Sons of Mogh")
In 2376, Martok suggested to Tarilla that she obtain adanji and die by the Mauk-to'Vor ritual. (ST - Klingon Empire novel: A Burning House)
Several crewmembers of the IKS Gorkon possessed adanji. (GKN novel: A Good Day to Die)