Some have a custom to put havdallah wine on the luz bone. Where is the luz bone located? Where on the nape of the neck?
The custom of placing wine on the Luz bone is mentioned in Keter Shem Tov (Ahavas Shalom, Vol. 1, p. 482), as the custom in Morocco and Tangier.
According to the custom, the Luz bone is the highest of the spinal vertebrae, in the area of the nape.