1. The white ring of powder which forms around the nostril in which has been used to snort a powdered drug.
2. 'Elton John' can even be used to name the drug itself. In a non-obvious way i.e, code name to use whilst in public.
The term has absolutely no reference to Elton John (the singer), it simply originated from when a group of people were fucked on illegal substances and couldn't name the drug for obvious reasons so they came up with a completely random name to call it. Not so long after, the name spread round different groups of people and soon enough everyone was using the phrase.
1. "Oi babes look at me, yeah yeah fix your elton john, its showing."
2. -"OH SHIT I FORGOT ELTON JOHN, I FUCKING LEFT IT BACK AT HOME.... "
- "nahh for real? you're gonna have to go back man, we need him tonight we're going clubbing!"