It was about 2 AM when Frisk had suddenly awoken from his sleep. He still felt a bit sleepy, but he quickly pushed himself up out of bed and looked around. He gave a soft, scared whimper, breathing deeply for a while, before finally getting out of his bed and shuffling over to Toriel's room, feeling that he had to talk to her. But as he was just about inches away, he stopped, looking around fearfully as he was not sure if he should wake his mother up. What if she got mad? What if she told him something was wrong? He couldn't bear to upset the kind, loving monster that had adopted him, treated him like her own son. The thought terrified him, and eventually he began to back off, going back to his room.
Unfortunately, he had been watching the door so intently that he hadn't watched his feet, suddenly tripping over them and landing on the carpet outside Toriel's door with a loud 'thump'! He panicked, quickly trying to scramble up and get back in his room, but just as he grabbed the doorknob to his room, he heard the door behind him get thrown open as Toriel came out, looking worried, but like she would take on a dozen men to protect her little boy. He froze in place, soon feeling the tension dissipate as she said, "Oh, m-, my child. It is you." Then, quickly coming over to him and turning him around, she asked, "Are you all right? Did you get hurt? Why are you up so late?"
He bit his lip in fear, not wanting to tell his mother what he was doing up, but eventually he mumbled, "I-, I'm fine, mom…I just tripped."
She gave a relieved little sigh, but soon began to roll up his pantleg, saying, "I am glad you think so, but why are you up this late? It is past your regular bedtime."
He looked away, mumbling, "It's, n-nothing. I just, w-, wanted a midnight snack. Th-, that's all…"
Recognizing a lie when she heard one, she soon pulled Frisk's pajamas back into place and said, "My child, please do not lie to me. If there is something wrong, tell me."
Frisk looked around, shame creasing over his already worried features as he found himself at a loss for words. But finally, he looked up at her with big, scared eyes, eyes that Toriel had not seen since the first time she met him in the Ruins. "Do you promise, n-, not to be m-, mad…?"
She was completely shocked to hear these words come from Frisk's mouth, wondering what could possibly be so awful that he couldn't even tell her what was wrong. Then, finally, she gave her son a warm, loving smile and whispered, "I promise, whatever it is, my child, I will not be mad."
Then, after a few seconds, Frisk nodded and whispered, "O-, OK…I, I had a, a really weird dream a while ago…"
Raising her eyebrow up, she asked the boy, "W-, was it, a nightmare? Did you have some sort of scary dream? If so, then you need not worry, my child. It wa-"
"It, it wasn't a nightmare, mom," Frisk quickly stammered. "At, at least I, I don't think it was…"
Toriel was now really unsure of what to say, trying to consider what Frisk was telling her. 'Not a nightmare? But, what sort of dream could my child have that would leave them so-' Then, as she looked down and noticed Frisk was hunched over, hands pulling the shirt of his pajamas down as much as he could over his pelvis, it clicked! And, with an uncertain tone, she asked Frisk, "This dream you had, did it involve someone without clothes, or something similar?"
Eyes going wide as she said this, he stammered, "Y-, yeah. How, how did you know?"
Patting his shoulder comfortingly, she said, "I have some experience with this, my child. Come, let us go downstairs, and I shall explain everything to you." Then, taking one of his hands, she led him into the living room and sat with the boy on the couch. "Now, first…Forgive me for having to ask, my child, but are you a boy, or a girl?"
Blushing a bit, Frisk mumbled, "B-, boy…"
She nodded in response, saying, "I see. Thank you," before taking a set of sheets and showing one to Frisk. It was an anatomical diagram for a man, and she explained, "You see, my child, since you are nearing the age of 13, you are going through something called puberty. It is the biological transition from a child into an adult, and it causes many wonderful, but very confusing and even scary changes to occur."
Nodding a bit as he heard this, he then nervously asked, "And, m-, my dream, wh-, what about, ummm, p-, pu-…that thing, what's it have to do with that?"
Patting his shoulder, she told him, "That, my child, is called a wet dream. You see, when a boy or girl really likes someone or something, whether they be girl, boy, human, or monster, sometimes that can cause arousal. This feeling is a special feeling that means something about that person excites the person feeling it. This arousal, if it becomes strong enough, can, for boys, cause their penis to become erect, and if it gets even stronger, causes them to release something called semen. I'll explain what semen is another time, but to get back on topic, a wet dream is a dream that arouses the person having it, and can cause them to release semen. So, to put it in the simplest of terms, there is nothing to be ashamed of because you had a wet dream. It's just a natural part of life that almost everyone experiences."
Hearing this, Frisk looked a little amazed at first, then relief flooded over him, and he said, "S-, so, then you've had, ummm, wet dreams?"
She blushed a bit before nodding in response, telling her son, "Yes, Frisk, I have."
Turning to her, he then asked, "What were the wet dreams you had about?"
Blushing more, she quickly told the boy, "That, really is not an appropriate question to ask someone, my child."
As soon as she said this, he looked horrified, hugging his furry mother, and saying, "I-, I'm sorry. I didn't mean to say it, really!"
She gently shushed the worried boy, stroking his head, and reassuring him, "It is fine, my child. You did not know. Just remember in the future that there are some things you can say or do that are not appropriate."
He nodded into her soft chest, telling her, "I won't forget, I promise."
"Good," she said with a smile. "Now, you really should go to bed. Though you should probably change first. You would not want to go to bed with wet clothes."
He just blushed, pulling his shirt down over his wet pajamas again, and said, "Yeah, right…" before rushing up to his room to change. Toriel, wanting her son to have his privacy, waited outside until, finally, he opened the door a crack and handing her a bundle of clothes, the pajamas and underwear he had on before, which she placed into the laundry bin.
Then, before she could go back to bed, she felt a hand grip her nightgown, looking back to see Frisk there, clothed in new pajamas and looking a little nervous. "Ummm, d-, do you think, you could teach me more about p-, peeyuu…"
She smiled, saying, "Puberty, Frisk. And yes, I would be happy to teach you more."
A smile as brilliant as the sun quickly came to his face, and after tightly hugging his goat mother around the waist, he said, "Thank you, mom," before slipping through his door and getting back into bed.
Toriel just stood there for a while, smiling at her son's door, before whispering, "You're welcome, my child," turning around, and going back to bed as well. And as she thought about talking with Frisk, she couldn't help but eventually fall asleep, a slight sense of pride warming her as she imagined her loving child growing up into a man.
