I smell my hands when they get sweaty or dirty

So basically, I have developed over the years this weird habit where i almost subconsciously smell my hands. Ill take a good whiff of my hands by covering my nose with my palm and cupping my face with my fingers. I tend to do it more when ive touched sweaty metal from working out, or a place that has cigarettes and has stale air floating around in the room. Once i touch enough things in there, like a casino or something, and i begin to sweat from my palms thats when i get the biggest whiffs, why? Because it stimulates the hell out of me, almost like a drop of morphine for me every time i get a whiff. I want to stop, but ive been doing this for years and it only gets worse...