For the effects of (one guess at a) witches' ointment, look on the web at the Vaults of Erowid for a description (insofar as she could remember it) by a woman in Slovenia who tried it. She was rather lucky to emerge from the experience alive, but didn't regret it.

Somewhere I have a German ethnobotanicohistorical journal of psychedelics with a long article (in German, which I don't read very well) suggesting that witches' ointment was mostly mythical, with the formulas all invented long after the fact.

There is an interesting take on paganism in the writings of Carlo Ginzburg, particularly "Ecstasies". Try that stuff in song and you would *really* give your audience the willies.

Another weirdly different book: Martenengo-Cesaresco's "The Stufy of Folksongs", which mainly focuses on southern Europe. She's very good on the stuff that emerged from interactions between paganism and Catholicism.