Her crime for claiming herself as ‘bestesh babbeh’ has been way overpunished, as it should be. But letting her die now in pain and misery, knowing that she only has herself to blame, feels like a good closer to her character.
She’s a dummy now. She’ll forever be marked as inferior in the eyes of any other Fluffy.
The emotional misery of eternal frustration is better than physical punishment. The idiots can never acknowledge her as what she sees herself to be, has no way to communicate her demands or rage, and if she shits outside the box the sweeter of the others may simply assume she’s Sensitive and treat her as such by cleaning up after her, increasing her rage at the world with the conundrum of throwing a fit or making them think she’s not mentally handicapped.
Plus, she can still make mouth sounds. Even more frustrating, so close to words and entirely unable. Trying to stick things in her mouth as tongue replacements only to hurt herself then be disappointed.
I’ve not read your story, but the old writer’s advice to “kill your darlings” is just as wise in fluffy writing as anywhere else.
In my opinion, the more you like a fluffy you’ve created, the more likely it should suffer/die/suffer and die (and by orders of magnitude). If you as the writer feel sorry for what you’re doing to the fluffy, then it’s more likely that your readers will feel sorry for it, too.
Of course, this advice does not apply to works of undiluted, saccharine hugbox.