Asriel had done something very foolish. He had made a bet with Frisk that he would perform better in their final English exam before Spring Break and if either of them lost, they would have to wear woman's underwear for a week. Needless to say, Frisk got a better grade than Asriel, so the goat was given some underwear to wear for the week and Asriel made it his mission to hide this from his parents.

When Toriel took the boys to the local spa pool to help relax after the stressful school period before, Asriel had found that Frisk had pre-packed some swimsuit panties to wear on their trip. Asriel was fretting over this and thought about bailing if his mom were to find out, but he had no other choice, he fit the panties on his feminine form as the fabric covered his half erect member as he checked himself out in the mirror, "Well, I don't look too bad... But mom is going to ask some serious questions about this..."

As he walked to the pool, he found his mom sitting by the pool ledge, her legs submerged in the water. Surprisingly, the pool was quite barren besides the two of them, Frisk was lounging on a massage bed nearby but Asriel could tell the human was watching him. He sat beside his mom and found another realisation, she was completely naked​.

She turned to her son and smiled warmly, "Hello, sweetheart. So nice of you to join me here."

He nodded and murmured bashfully, dipping his legs into the warm waters. Toriel looked around and remarked, "The water is lovely, wouldn't you agree?"

Asriel smiled briefly before turning his attention from her bare breasts, "Oh yeah, water's great..."

"It is so nice to get away from school work after all those exams. You two have done so well this semester." She added, smiling back at him.

Asriel simply nodded, mustering the courage to look at her. "Yeah, really helps..."

"It is just a time to simply relax and take in everything around you."

The young goat chuckled slightly, his confidence returning. She hadn't mentioned the panties yet, or the erection forming between his legs as he blushed deeply. Maybe she had forgotten?

"I must ask, why the panties, Asriel?"

She was staring right at it. This wasn't good.

Asriel stammered, "Ah, er... Y-you see mom, there's a f-funny story about that--"

"Don't you think they are a bit small?"

Asriel raised an eyebrow, "Come again?"

"You do not have to wear them, you know. Heck, I am not wearing my top, clothing isn't necessary here if you do not wish to wear it."

The goat mentally breathed a sigh of relief and chuckled, pulling at the tied string and shedding them, his member flopping free, "Yeah, I guess you're right."

Toriel gave a chuckle and shook her head, "Do not think I do not know, Asriel."

The goat child looked at her in confusion, Frisk raising an eyebrow, "Mom, what are you--"

"I have heard you and Frisk talk about this, you were made to wear them, were you not?" She asked, making sure the last few words were loud enough for Frisk to hear them.

Frisk tried to move, but felt levitation magic hold him in place. Frisk was truly screwed now.

Asriel gave a wide smile, "So you knew the whole time?"

"A mother always knows, my child." Toriel smiled back, bringing Frisk to her as he hovered in place in front of her.

Frisk stammered, "Mom, f-funny thing was that is was kind of Asriel's idea too--"

"Don't pin this on your brother, you naughty boy. Do you not think he has suffered enough? Imagine the embarrassment if others were here!" She exclaimed, keeping a stern, yet mischievous tone.

Toriel looked at Asriel and asked, "What should we do with him, Asriel?"

The goat child stood up and replied, "Throw him in the pool, I have a few things up my sleeve."

With a flick of her wrist, Frisk was sent flying into the deep end of the pool as Asriel dove in after him. The human landed with he felt a pair of paws at his legs and was dragged under. The two surfaced shortly afterwards​ with Asriel holding the human's shorts in his paws before tossing it to his mom as she caught and threw them aside.

Frisk exclaimed, "Hey, give those--" His cries were silenced by a large wave of water splashing into his face, Asriel and the human engaging in a splash fight/wrestling match, the two brothers laughing before their mother joined in and dunked the two before diving after them. They surfaced and continued their splash fight, their laughter filling the room as they enjoyed the company they had.

Maybe Asriel hadn't made such a big mistake afterwards, not with a mom as awesome as his.