A Druid's Handbook to the Spiritual Power of Plants: Spagyrics in Magical and Sexual Rituals by Jon G Hughes, from Destiny Books, may be of interest. Apparently this was previously published as Celtic Plant Magic.
“In this practical guide to Druidic plant magic, Jon G. Hughes reveals the gentle alchemy of converting plant essences into potent compounds for working sex magic rituals. Examining the identification, harvesting, and magical properties of more than 70 flowers and trees, he details the careful and meticulous spagyric preparation of plant extracts and complexes as well as the process of obtaining or creating suitable alcoholic spirits for the base of these preparations. He includes instructions to make all necessary tools and explores how to prepare yourself to work with plant essences and properly use the magical compounds you create.
Hughes explains how to release the energies, healing attributes, and magical capacities of flowers and trees through the respectful seduction of a plant’s virtue and the 3-step spagyric process of separation, purification, and reunification. He shows how the spagyric process maximizes the power of the acquired essence in preparation for its use in magical ritual. Detailing Druidic sex rituals for both a couple and a group, Hughes demonstrates how plant compounds are used in specific magical rituals and practices as well as the role of the plant complex in sexual potency. Exploring the underlying accord between alchemy and Druidic practices, Hughes provides a valuable manual for anyone wishing to harness the magical potential of plant energy.”