Can you describe the specific service Mavshibai was performing for Sai Baba that led to the incident with Anna?

According to Chapter 24, Mavshibai, a widow whose original name was Venubai Kaujalgi, was a deeply devoted follower of Sai Baba. Her method of service was quite extraordinary and physical. While pressing Baba's stomach and side, she would twist and churn "like a pot of buttermilk." The text notes her service was so intense that her breath became uncontrollable and that she made Baba's stomach and back flat. It was during this swaying, zealous service that her face moved up and down and came close to Anna's face, inadvertently sparking their humorous misunderstanding.