nutsniffing
A psychological disorder falling under the larger diagnostic category of OCD whereas the sufferer, usually a contortionist, bends himself far forward enough to repeatedly and compulsively sniff his own nuts.
Sadly, I found out that my cousin is being treated for his debilitating nutsniffing illness and part of the treatment is for the patient to have to tightly seal their nuts in plastic wrap day and night, so the pleasure reward is taken away and the behavior gets extinguished pretty quickly!