Harmony is a character in a Warlock of Lust game. She is a mage apprentice and can be found at the magic Academy. After the Lust magic quest is completed, you can talk to Jennyfer about lust magic and she will suggest, Harmony can work with you to explore and improve your spells.
Talk with Harmony to perform various experiments to find out how spells can be improved. This quest is straightforward, just perform one experiment after another.
As of game version 2.2, you can improve "Spiritual dick" and "Mana orb" spell, but not "Carnal aura"