The "butt-bone" is scientifically referred to as the coccyx (pronounced cok-siks) I believe it is the remnants of when our evolutionary ancestors had a tail. Gradually, over the course of millions of years, the tail shrank until what remains to this day is the coccyx, or "tail-bone".
Drugs impact the brain because it causes abnormal growth which eventually forms tiny, almost mircroscopic little short hairy gnomes inside the oppicatal canal of the coccxy. This gnomes are very irritable but can be removed surgically. The gnomes will play padie wac on your pariential lobe. If you listen close enough you can hear the awsome reggie beat their banging out. After awhile the beat will infect your nerves, which becomes a pounding. Take two of theze and youll be fine.