Its a coke bullet. where there is white residue you fill with your favorite sniffable substance. Then you put the round piece in one of your nostrils and sniff til you run out and its daylight and your nostrils are all clogged and flared up and you would like to sleep but can't and your nose is killing you but you would really like another line.
I'm glad those days are long gone. I just blaze space cabbage and have a drink every few months.