To shoot the moon is when you intraveinously inject a large enough dose of cocaine to get what is considered a "bell ringer". During a bell ringer, the user gets tinnitus in the ears. One user details this experience as "To hear the 'train', the aluminum sound of the world being crushed--like the 'green room' of surfing". So to summarize, when you shoot the moon, youre taking the use of cocaine to an entirely different level than those who simply insufflate or smoke the drug.
-"Shooting the moon is an extremely bad idea and usually only leads to pain and misery in the end. Only the lucky ones get out unscathed."
-"As soon as I turned him onto using needles, he was shooting the moon and spending his every last penny on more cocaine."