In the case of Sonic, he might become more reliant on others. Normally, he's the one others rely on, but now in Tails' position, he might seek help more often. He could start to value teamwork in a different way. Tails, when in Sonic's body, might start to see the world in a more simplistic way. He's so used to analyzing everything, but now with Sonic's carefree attitude rubbing off on him, he might make decisions based more on gut feelings rather than careful consideration.
Another plotline could involve their relationships. Sonic, as the younger one, might be more naive in some ways and look up to Tails for guidance. Tails, in Sonic's body, could find it strange to be the center of attention and the one expected to lead. Their friendship dynamic would change completely. Maybe Sonic would start to envy Tails' natural intelligence more, while Tails would realize how much pressure Sonic was under all the time.
The combined personality could be a mix of Sonic's adventurous and fearless nature with Tails' intelligence and cautiousness. For example, they might be quick to jump into action like Sonic but also think twice about the consequences like Tails.
Well, Sonic Tails could save Sonic fanfiction by being a central figure that unifies different storylines. He has a strong connection with Sonic and other characters. Fanfiction writers can build around his relationships, his loyalty to Sonic, and his own growth as a character. His character traits can be explored in various ways, like his courage in the face of challenges. By being such a rich character to write about, he gives new life to Sonic fanfiction, preventing it from fading away.
Their interaction would likely be positive. Sonic, being the friendly hero, would probably greet Tails with a big smile. Tails would be shy at first but soon open up due to Sonic's warm attitude.
Sonic would be the first to react. He'd be angry and immediately start the search for Tails. Amy would be worried sick and might try to help Sonic in any way she can, like gathering information from the other animals in the area. Knuckles would be on high alert, thinking this could be part of a bigger plan to get to the chaos emeralds. He'd guard the emeralds even more closely while also keeping an eye out for any signs of Eggman's activities related to Tails' kidnapping.
Well, usually in these fanfictions, Tails meets Sonic during an adventure where they both end up at the same place by a series of coincidences. Their meeting leads to an exciting partnership.
In many Sonic Boom fanfictions, Tails often meets Sonic by chance during one of Sonic's adventures. Maybe Sonic is in trouble and Tails shows up to help.
In some fanfictions, Sonic Tails' parents are often portrayed as heroic figures. They might be shown as having great speed or intelligence, similar to Sonic and Tails. For example, they could be part of a resistance against an evil force in their own time.
Often, the meeting is set up as Sonic helping Tails out of a tricky situation and that's how their bond begins.
In many fanfictions, Sonic and Tails might meet through a chance encounter during one of Sonic's adventures.