I believe this song is about his feeling about his drug. 'She' is the drug. 'Everytime we fall down, she dances all over me' is a statement referring to everytime something happens, 'she' is the drug that dances all over him. 'she' is a good dancer and she will probably be the death of him hence 'she dances on my grave'. It's basically the 'feeling' he experiences while he's high, like she's his companion and her doesn't want her to float away, or be far from 'her'
I believe this song is about his feeling about his drug. 'She' is the drug. 'Everytime we fall down, she dances all over me' is a statement referring to everytime something happens, 'she' is the drug that dances all over him. 'she' is a good dancer and she will probably be the death of him hence 'she dances on my grave'. It's basically the 'feeling' he experiences while he's high, like she's his companion and her doesn't want her to float away, or be far from 'her'