Perhaps they call Peter in class because they've discovered some sort of conspiracy that involves the school or someone in it. Peter, being a friendly neighborhood Spider - Man, has a good sense of what's normal and what's not in his neighborhood which includes the school. They might need his help to investigate something strange going on within the school walls.
It could also be that the Avengers are planning a big team - up event and they want Peter to be part of it from the start. They know he is still in school, but they value his input and skills so much that they call him during class. This would show how much they respect Peter as a member of the team, even though he is also a student with normal school life.
Peter could also be very nervous. He's still a young hero and being called by the Avengers in such a public setting like in class could make him feel self - conscious. He might stutter when he tries to answer their call and fumble with his things as he gets ready to leave. He'd be thinking about all the possible things they could need him for and whether he's really up to the task while also dealing with the eyes of his classmates on him.
Perhaps it's his best friend who has some juicy gossip to share. But it's really bad timing as he's in class. His friend might not be aware of his class schedule.
One scenario could be that Harley gets more attention from a love interest. If there is a shared love interest in the fanfiction, and Harley is always getting the girl or boy's attention, Peter would be jealous.
Well, he might get in trouble with the teacher. Teachers usually don't like students getting phone calls during class. So, the teacher could take his phone away and give him a detention.
One common scenario is after a big battle. Picture this: Peter has been fighting alongside the Avengers against a horde of powerful enemies. He's been using his spider - powers non - stop, swinging around, shooting webs, and getting hit a few times. By the end of the battle, he's just physically exhausted and faints right there on the battlefield.
Perhaps in the fanfiction, there is a malfunction in Peter's suit technology. It could be that the suit's power source goes haywire and causes an explosion that kills Peter. This could be due to some sabotage by a new enemy who targets Peter specifically because of his growing reputation as Spider - Man in the Homecoming universe.
The Avengers meeting Peter's girlfriend could also bring out a protective side in Peter. He might be worried that they'll be too hard on her or that she'll be in danger just by being associated with them. Meanwhile, his girlfriend could be trying to fit in and prove that she's worthy of being around such powerful heroes. It could also be a situation where she has to deal with the jealousy of some of the Avengers' female members, if there are any. Or she could form a special bond with one of the Avengers, like Natasha Romanoff, who could become a mentor - like figure to her.
Well, it depends on who's calling. If it's Tony Stark, for example, Peter would be super excited and might not be able to hide it. He could try to come up with some lame excuse to leave the class, like saying he has a stomachache. But the teacher might not believe him. And his classmates would be curious about who's on the other end of the call.
Maybe Peter was doing a science experiment in class and something went wrong, like a chemical explosion that injured him. The other students could be in shock and the teacher would have to quickly take action to get help.
One possible reason could be a misunderstanding. Maybe Peter accidentally gets involved in something that looks bad to the Avengers, like being in the wrong place at the wrong time during a security breach. So they misjudge him and are mean as a result.