The "Cinnamon stink" is ones Butt hole, more specifically the "O-ring". To further understand this term, one should break the term down. "Cinnamon" is used because of the Butt hole's often brown appearance. Also "Cinnamon" is used in this term because of the rear end's abundance of residual pieces of fecal matter (look up the term "dingle berry". The word "Stink" is used in this term because of the area's obvious unpleasant odor.
"I just spread my cheeks and the bitch ate up my Cinnamon stink!"