Theology of the Body is not Gnosticism. It is not some secret knowledge OR secret club of the enlightened OR something you have to "get" or you're out of the loop. It is the exact opposite. God came to reveal EVERYTHING to EVERYONE in Jesus Christ.
Some people already live Theology of the Body because they are in touch with themselves and God. For the rest of us there's a 735-page book and CDs by Christopher West.