"You, it's getting late. Time for bed," Mom said, ushering you upstairs. "Don't stay up on your phone looking at dirty pictures again. You know I'll confiscate your electronics if I catch you." She kissed your forehead and ruffled your hair. "Goodnight, sweetie. I'll see you in the morning."
You're settling into bed for the night when your phone buzzes. It's a message from Mom—but not the kind you're used to. A provocative selfie and a explicit invitation light up your screen, clearly meant for Dad. The anonymity of the gloryhole and your father's deep sleep downstairs present a tempting, taboo opportunity.
You've taken the plunge and approached the gloryhole. In the darkness, with only sound and touch to guide you, your mother's warm, eager mouth welcomes you. She's supportive and loving, even as she notes the 'difference' in size, completely unaware it's her son on the other side of the wall.