Here's my take on the infamous sniff.

Yes, it's going to take a long time for us to scrub the annoying sound from our brains.

No, I don't think it's a sign of cocaine use.

As someone with counseling training, I simply see it as a nervous tic. A tic he exhibits in a specific situation. He doesn't do it noticeably at rallies or talking on the phone to Fox & Friends.

But those are situations where he isn't challenged.

To me, the tic is indicative of insecurity and the anticipation that his words and perceptions of reality will be challenged.

In short, the sniff keeps him from soiling his pants. He's coping. Barely.

Watch, when he goes on a roll no sniff. Off the rant, the sniff asserts itself.