Can you describe the specific ways Mavshibai and Damu Anna were serving Baba during their argument?

Certainly. During the incident, Damu Anna and Mavshibai were both engaged in physically serving Sai Baba. Chapter 24 explains that Anna, who was over fifty, was leaning forward from the outside and slowly pressing Baba's left hand. In contrast, Mavshibai was performing a much more vigorous service. She was pressing Baba's stomach and side with such intensity that she was 'twisting with both hands' and 'grinding' his stomach, churning it 'like a pot of buttermilk.' This 'extraordinary way of pressing' caused her to sway back and forth, which ultimately led to the humorous confrontation with Anna.