Enter "press X for doubt" meme...
If you sleep only in the hay stack, maybe.
as far as I recall she looses affection if she get's pissed with MC getting touchy before a certain Level of corruption.
If you're at the beginning of her content, you're just softlock in her progress, IIRC she won't go past 6 if you don't visit her mom in the afternoon and progress her story, some characters in the game (if not all) have a softlock on them Corruption/Affection that won't increase until you advance in their respective plots.
You can't really visit her mother until Tia herself invites you back to her place. You need to chop wood and talk with her, one of the topics about her past will make her go awkward and stop talking, so you need to then visit Rick to ask him about Tia when he is sitting on the bridge. After that you can talk to Tia again about the topic and you can then continue progressing her story.
Oh right I forgot about this part, but my point was that if he is on the begining of her story he don't need to edit her affection with save edit or something, this is probably is just gonna break the game latter, he just need to progress in her story and he will be able to increase her affection/corruption.
The option is likely red as it triggers Events that lead to the Party to break up as Tia won't be available until you regroup with her after that choice... so better save up beforehand and get any Quest done that might need her assistance, the battles to follow on her story are also the toughest ones as of yet
