Lyric discussion by Mrkhan1024 

Cover art for Sledgehammer lyrics by Peter Gabriel

The song is about sex. Don't overthink it. All three verses are clearly referring to sexual acts or sexual parts, and others have explained it perfectly above. Even the video begins with swimming sperm, and the last fruit he eats is a cherry.

The one line the "drug" proponents point to as the start of their explanation is "I've kicked the habit." A habit is also a religious garb, typically worn by nuns, monks, and other religious orders. Kicking the habit is followed by shedding his skin. The combination of those two suggests throwing away his inhibitions and/or peeling off his clothes. It is a great play on words. Enjoy!