Lyric discussion by sound_of_silence 

Cover art for Grey lyrics by Ani DiFranco

"you penetrate me and my little pink heart is on its little brown raft floating out to sea"

This part always struck me as a metaphor for sex.

"you penetrate me and my little pink heart is on its little brown raft floating out to sea"

Ani speaks of a needle entering her skin.. "and my little pink heart is on its little brown raft" Ani refers to Heroin is this verse.