I made this story long ago, but I'm still getting on top of my other stories ouo I didn't see any R+18 stories based on the one event, though I think the idea is popular with Mary reading it. I blame a live-stream which inspired this one-shot so it's partially head-canonish.
Warning: contains sexual humor.
Shortly after the separation incident, Ib and Mary were focused on wandering around but the blonde girl was keen on something else. The brunette? She was a little nervous on leaving Garry by himself, but his smile assured her temporarily as they wandered opposite or the direction they were meant to go.
Within a few minutes, they stumbled upon the room where it was once covered in the ominous lettering all around the room. Oddly enough, it didn't faze her as the eerie warning had faded.
Mary hummed a tune as she frolicked around the room. Ib, on the other hand, looked through the book which Garry had seized from her earlier. She couldn't grasp some of the vocab though. The words were simply on the page:
'? by the ?, I ? my finger over her beautiful ? With her ? she …'
"Ib what are you doing?" Mary suddenly asked.
The girl who was reading the story shut the book with an embarrassed and sneaky look on her face. It was almost deviant, but Mary merely grinned with such innocence without even attempting to scold her. Relief settled into her, but Ib figured nobody would let her curiosity be satisfied.
The blonde girl eyed the book before roughly snatching it and skimmed through the pages, her eyes furrowing. After a moment when she reached the back cover, she closed it and shrugged.
"It's nothing to be afraid of!" Mary flashed another grin. "It's just a man offering his clever hands to a woman's body."
Ib quirked a brow, but said nothing. Why do men touch another women to the point she did something? It made her mind ill just trying to figure it out. Well, Garry never did anything like that. He kept his distance.
Mary took the silence as a sign to carry on. "It's a process where two people go on this bed and have sex!"
"S-Sex?" The brunette inquired. "Isn't that the bed where people sleep?"
"It's more than just for sleeping, silly!" The other girl giggled. "They do all sorts of things!"
Mary explained to Ib about the story itself and filled in the blanks for the words she didn't not understand. It only took half an hour before Mary's mouth went dry from talking and they remembered they needed to go back to unite with Garry. After doing the puzzles, they reunite with Ib hugging Garry and so forth.
While they were walking, Ib looked up at her brotherly companion. "Garry?"
Garry looked down towards the girl. "Yes, Ib?"
"Is it true babies come from having sex?"