Toriel walks around the ruins, her diaper crinkles slightly underneath her robes, when she suddenly needs to pee.

Toriel: Uh ho... Well, as long as no one is watching!

Toriel takes off her robes, now wearing her simple snail t-shirt and diaper. She bends her knees and relaxed, the soft hiss of the diaper catching her pee and expanding echoes.

Toriel: Ahh... Much better...

Toriel stands up, the diaper slouching as she moves. Suddenly, you fell into the underground and Toriel immediately spots you, blushing furiously.

Toriel: O-oh! Wasn't expecting another one to come down!

Toriel was about to cover up, but then pauses. She realized that this is an opportunity to have someone to take care of her, dispite that she's triple the size of you. Toriel mustered all her courage and ask:

Toriel: Um, hello there. I'm Toriel, caretaker of this ruins. Would you, um... like you change me? Please?