In Teen Wolf fanfiction, 'a wolf in sheep's clothing' could refer to a character who appears harmless but is actually dangerous. For example, a new student in Beacon Hills who seems friendly and ordinary at first, like a sheep, but later turns out to be a powerful and perhaps malevolent werewolf, a wolf in disguise.
There are many Teen Wolf fanfictions that focus on Stiles in a more appropriate way. You can look for ones on fanfiction.net or Archive of Our Own. Just search for 'Stiles' and filter through the results to find stories that match your taste without the inappropriate content.
One example could be a character who pretends to be a hunter ally but is actually a werewolf working for a more sinister force. They might use their guise as a hunter supporter to get close to the pack and gather information for their evil masters.
There could be a story where a gay teen wolf is bullied by other wolves in the pack because of his orientation. However, he doesn't let it break him. Instead, he finds strength in his identity and uses it to protect the weaker members of the pack, becoming an inspiration for all those who are different.
Imagine a story where the Deathly Hallows are in the Teen Wolf world. The Teen Wolf characters don't understand what they are at first. But then they team up with some HP characters who have come to retrieve them. They have to battle a powerful dark force that wants to use the Hallows for evil in the Teen Wolf realm. This would combine the magical elements of HP with the action - packed werewolf lore of Teen Wolf.
There might be a story where a gay teen wolf is an outcast not just because he's different in terms of his sexuality, but also because he has unique powers compared to the other wolves. He then has to find his place in the world, both as a gay individual and as a special wolf.
One popular teen wolf adult fanfiction could be those that explore the characters' post - high school lives and their new challenges in the adult world. For example, stories where Scott has to deal with being a leader in a more complex supernatural society as an adult.
One positive aspect is his intelligence. In fanfiction, it often shines through as he devises plans to deal with the various threats in the Teen Wolf world. For example, he might figure out a way to outwit a new supernatural enemy.
The integration with the existing Teen Wolf world is crucial. The fanfiction should feel like it belongs in the same universe. This means referencing the right locations in Beacon Hills, the existing characters like Derek Hale and Stiles Stilinski, and the rules of the supernatural world in the show. If the werebear's presence disrupts the established order in a believable way, it makes for a great story.