She loves it.

Your Mom and Emma's Dad stare at each other in silence. He's sitting on the toilet, stroking his titanic dick, and she's standing in the open doorway trying not to make any sound. She wordlessly mouths a "Wow" to Emma's dad, showing how impressed she is. He shyly tries to play it off, seeing this as an accident that can be acknowledged but not discussed. But your Mom has other ideas. She steps inside, leaving the door open, just risky enough that somebody could walk by, and licks two of her fingers. While Emma's Dad sits, dumbfounded, she runs the two fingers from the base of his cock up to his head, briskly. He shudders in place as his hormones start to take over his higher reasoning, and to put the cherry on top, your Mom returns the fingers to her mouth before stepping back out again and closing the door behind her. After all, she has appearances to keep up.

Soon, she and Emma's Dad have both rejoined you in the living room, each with dirty thoughts for the rest of the night.