One way is to create comical situations around their relationships. Say, the man in the woman's body tries to flirt with his own girlfriend, but does it in a really awkward way that only the woman's body could pull off. And the woman in the man's body has to deal with the man's nerdy friends and ends up making them do girly things like having a tea party. Add in some funny dialogue where they keep accidentally using phrases from their own gender's vocabulary in inappropriate situations.
One interesting plot twist could be that they start to understand each other's daily struggles much better. For example, the man in the woman's body realizes how difficult it is to deal with catcalling when walking on the street. Another twist could be that they fall in love with their own friends while in the other's body, creating a very complicated love triangle situation. And also, they might find out secrets about each other's work or family life that they never knew before, which changes their relationship completely.
I think Iron Man and Hulk would be a really interesting pair. Just imagine Tony Stark's brilliant mind trapped in the Hulk's huge, rage - filled body. He would be constantly trying to find a way to control the Hulk's strength and not go on a rampage. And Hulk in Tony's body would be so confused by all the technology and might accidentally set off some of Stark's weapons.
There was a young man, Jack, who through a magical spell switched bodies with a girl, Emma. Jack, now in Emma's body, was astonished by the change. He realized that Emma had a very different daily routine. He had to attend ballet classes which he initially thought would be easy but turned out to be quite difficult. As he spent time in her body, he became more empathetic towards the female experience, like the pressure to look a certain way. Eventually, with the help of an old wizard, they switched back.
Once upon a time, there was a girl named Lily and a boy named Tom. One day, they both touched a strange old mirror at the same time in an antique shop. Suddenly, they found themselves in each other's bodies. Lily, now in Tom's body, was shocked to see her new male appearance. She had to deal with Tom's football practice. Meanwhile, Tom in Lily's body had to attend ballet class. In the end, they worked together to find the same mirror again and reversed the situation.
If Black Cat and Spider - Man switched bodies in a fanfiction, it would be a total chaos. Spider - Man would have to deal with Black Cat's more stealth - based and morally ambiguous tendencies. Meanwhile, Black Cat in Spider - Man's body would have to handle the great power and great responsibility thing. She might use Spider - Man's powers in more self - serving ways at first, until she realizes the true meaning of being a hero.
There could be a scientific experiment gone wrong. For example, they are in a lab for some school project on teleportation or something similar. But instead of teleporting, their minds or consciousness get transferred to each other's bodies. Another way could be through some kind of alien technology. An alien device that was meant for something else malfunctions and causes their bodies to switch.
Well, the plot could be that one day, after touching a strange old object, a boy and a girl suddenly find themselves in each other's bodies. They then have to navigate each other's lives. The boy, now in the girl's body, has to deal with things like wearing skirts and dealing with girl - friends' drama. And the girl in the boy's body has to play sports and hang out with the boy's rowdy friends.
It could end with them finding a way to reverse the body switch, like by finding another magical item or fixing the scientific experiment that caused it in the first place.
One moral could be about empathy. When the girl and boy switch bodies, they get to experience the other's life directly. For example, if the boy is used to more physical activities and the girl to more gentle ones, they understand the difficulties of the other's world. It shows that we should try to understand others' situations better without just assuming.