Massive Womanizer

"Sarah with... Mother? Whaat?"

After hearing my coherent question, Big Sis was clearly bamboozled, and she relentlessly glanced at them with a perplexed look in turns several times. Not only her, but Mary was also shocked by it. 

"Sarah..." Big Sis stared at Sarah and then turned her face to Mother. "And Mother...?"

Sarah's face was beet red as she glanced down, clearly embarrassed. On the other hand, Mother had been avoiding her gaze from any of us while wearing the same red face. The way they batted an eyelid at my theory, it seemed that I was right.

"Mother, would you care to explain the details to us?" 

"Ah—!" 

The moment Big Sis called her, Mother suddenly came to her senses, and her whole body twitched. I could sense that she was trying to stand and then escape, but Mom held on to her wrists tightly, rendering her plan to break loose from the issue unsuccessful.