A sexual act. The MM requires that the partner with long hair be on top of the other so that the head of the partner with the hair is over the others feet. This necessitates some variation of reverse cowgirl and should be done with care since the partner on top will be using their hands, which would normally be supporting themselves, to use their hair to wash the feet of the other partner with sensual oils or motion lotion.
Jesus: "Wow! My mind is still blown. She put the Mary Magdalene on me last night."
John: "Really? What kind of oil did she use? I'll bet your feet are still really clean and soft."
Jesus: "I think she used olive oil. Whatever. It was the bomb yo!"