Lilith is the priestess that has a headdress similar to a nun in the centre of the board, Level 2, and can be awakened by landing the ball in the cage centred in her forehead.
She has three stages: Asleep, Awakened and Enraged.
When you awaken her after dropping the ball in the cage the first time, you will begin to see her visibly deteriorate with each successive dunk. When you finally cause her to become enraged, the achievement will pop.
It took me 7 dunks but I have heard varying numbers from 5-15.