Lyric discussion by headlessparrot 

Cover art for Belly Button Window lyrics by Jimi Hendrix Experience, The

Hendrix's bassists' wife was pregnant (I don't think it was Noel Redding, but another one whose name escapes me) and Jimi thought it was like the coolest thing ever, and he was convinced that the fetus could see out through the belly button - hence, "Belly button window." Nothing sinister about it, and a beautiful (if somewhat underproduced, due to his early death) song.