Doesn't have to be drugs, it could be something about doing something filthy (not literally but like betrayed someone as in "Oh you know he did it, I can smell it on him" or betrayal as in "I smell a rat" because it talks about the person or whatever as sneaky and selfish (the shrewd)
Doesn't have to be drugs, it could be something about doing something filthy (not literally but like betrayed someone as in "Oh you know he did it, I can smell it on him" or betrayal as in "I smell a rat" because it talks about the person or whatever as sneaky and selfish (the shrewd)