system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: when people do coke in movies, what are they actually sniffing?
gpt
Lots of different recipes.  For snorting they use powdered lactose,  or a vitamin b power if there are lactose intolerance issues.   Also,  if the actor is using a straw or something to snort it,  they will coat the inside with Vaseline so very little will actually go in the nose.   Snorting anything will cause congestion.