In a fanfiction, Sonic and Tails could stumble upon a village where the main product is a unique type of milk. The villagers are being harassed by a group of badniks who want to take over the milk production. Sonic and Tails decide to help. They use the milk in creative ways, like using it to make slippery paths for the badniks to slide on, and ultimately drive the badniks away and save the village.
One idea could be that Tails and Sonic are on an adventure in a new land where they discover a magical milk spring. The milk has special powers that can give them extra speed for a short time. They have to figure out how to use this new discovery to defeat an evil villain who is trying to steal the milk for his own dark purposes.
Maybe Sonic and Tails are on an adventure and they come across a magical cookie that gives them special powers. They have to figure out how to use these powers to defeat an enemy. It could be a really exciting fanfiction with lots of action and the added element of the mysterious cookie.
In a fanfiction, one could have Tails and Sonic sharing cookies and milk while Sonic is bored. Maybe Tails tries to cheer Sonic up by making different shapes with the cookies, like little rings to remind Sonic of his super speed.
One possible plot could be that Sonic yells at Tails because Tails made a risky decision during a mission that almost put them both in danger. For example, Tails might have tried to take on a powerful enemy alone without waiting for Sonic's backup.
Well, Tails could be inventing a new device that needs milk as a component. Sonic, being curious, helps Tails gather the milk from different sources in their world. For example, they might visit a dairy farm run by friendly animals. Along the way, they face some challenges like avoiding Dr. Eggman's traps while transporting the milk back to Tails' workshop.
Maybe Sonic is in a slump, bored with the daily routine. Tails, sensing this, decides to bring some cookies and milk. They sit under a tree, and as Sonic enjoys the cookies and milk, Tails tells him about a new place he's discovered that they could go and explore. This way, the cookies and milk are a way to bring them together and the idea of exploration ties in with their characters.
Well, in some fanfictions, Tails might get injured during a battle with a new and powerful enemy. Maybe this enemy has some special ability that catches Tails off - guard, like a force - field that he doesn't detect in time and it slams him into a hard surface, causing an injury.
One possible reason could be a misunderstanding. Maybe Sonic accidentally broke something of Tails' while on a high - speed chase. Tails, being a bit sensitive about his inventions, might get angry and start a fight.
One possible plot could be that there is a powerful new item in their world. Sonic thinks it should be used immediately to stop Dr. Eggman, but Tails believes they need to study it more first. This disagreement leads to a fight as Sonic tries to take the item by force and Tails tries to stop him.
Maybe Tails was tinkering with Sonic's shoes or some other personal item without permission. Sonic values his stuff and his independence. If Tails was messing around with his things in an attempt to 'improve' them but instead caused a problem, Sonic would likely be angry.
One possible reason could be a difference in opinion on how to handle a particular threat. Sonic might be more impulsive and want to rush in, while Tails, being more cautious, would prefer to plan first.