Sniffing the Hanky
Sniffing the hanky is a term referring to doing cocaine. It is used in real life, WWII.

In WWII Swedish scientists made a hankerchef made out of blood and cocaine. It attracted German search dogs, then jacked their nose temporarily. It was served to hide the Jews as they were shipped to Sweden.
Hey, you've been sniffing the hanky?
No. I got high off of something else.