One possible scenario could be that Percy got injured and Annabeth needs to tend to his wounds on his torso, so she takes his shirt off. For example, he might have been scratched by a monster during a battle, and she has to clean and bandage the wound quickly.
In the context of a fanfic, there could be a bet or a dare involved. Percy lost a bet or was dared to let Annabeth take his shirt off. This could lead to some humorous or interesting interactions between them as they both deal with the situation.
Well, it could be a sweet moment of intimacy between them. Maybe they are in a quiet place, just enjoying each other's company and having a deep conversation while in that position.
It's Annabeth and Percy. Their relationship is being highlighted through this physical closeness. They may have different personalities and backstories within the original story that the fanfic is based on, and this moment of Annabeth sitting on Percy's lap can bring out different aspects of their relationship, like their protectiveness of each other or their mutual understanding.
Sakura might blush a bit and scold him for being so carefree. She's always been a bit more proper, so Naruto's shirt - off moment could catch her off - guard.
It could be a story where Percy takes his shirt off during a training session. Maybe he's getting ready for a really intense sparring match and removing his shirt is part of his pre - fight ritual to show his determination and focus.
This is a very disturbing and unethical concept. In the Percy Jackson series, Annabeth and Percy are friends and equals. Turning one into the other's slave in fanfiction goes against the positive values of friendship, respect and equality that the original work promotes.
One possible reason could be that she suspects Percy has some sort of mark or injury on his torso. Maybe they were in a recent battle or encounter and she wants to check if he's okay.
Annabeth could be one of the main characters interacting with him. She might tease him about taking his shirt off, or she could be concerned if he's taking it off because of an injury. Their relationship is complex, and this situation could add a new layer to it.