Peter would probably be really confused at first. He looks up to Tony, and suddenly being kidnapped by him would be a huge shock. He might try to talk to Tony, asking him why he's doing this.
Well, perhaps in the fanfiction, Tony kidnaps Peter because he believes Peter has some sort of secret that could endanger the world if it gets out. He might be trying to protect the world in his own, extreme way. And Peter is left confused and scared, having to figure out how to convince Tony he's on the right side.
Well, perhaps Tony has some sort of misunderstanding. Maybe he thinks Peter has betrayed him in some way, so he kidnaps Peter. But later, as he realizes his mistake, he tries to make it up to Peter.
A fanfiction might involve Peter Parker and Tony Stark being kidnapped during a mission. They are held in a high - security facility. While kidnapped, Tony uses his wits to analyze the security system, and Peter uses his enhanced senses to gather information about their captors. Eventually, they manage to outsmart their captors and escape.
Well, they could be kidnapped by a mad scientist. The scientist might be interested in Peter's spider - DNA and Tony's Iron Man suit technology. Once kidnapped, they would first try to assess their situation. Tony would probably look for any weak points in the confinement area, while Peter might use his spider - sense to detect any incoming danger or opportunity for escape.
It could be some disgruntled former employees of Stark Industries. They might feel that they were wronged by Tony in some way, like being fired or not getting the credit they deserved for their work. And they see kidnapping him as a way to get revenge. Peter might just be collateral damage since he is associated with Tony.
Yes, there might be. Fanfiction covers a wide range of scenarios, and a 'Peter Pan kidnapped' concept could exist. You can search on popular fanfiction websites like Archive of Our Own or FanFiction.net.
Peter could stand up to Tony. By showing his strength and not taking Tony's meanness lying down, he might earn Tony's respect. For instance, if Tony makes a snide comment, Peter could give a smart comeback that makes Tony see him in a new light.
One aspect to consider in 'possessive Tony and Peter fanfiction' is the nature of their relationship. It might explore themes of protection. Tony could be possessive in a way that he wants to keep Peter safe from the various dangers in the Marvel universe, like powerful villains.