The physical closeness of Merlin sitting on Arthur's lap can be the start of a deeper emotional connection. Arthur might become more aware of Merlin's vulnerability, which could lead to him being more open and caring towards Merlin in general. For example, he could start sharing his own insecurities with Merlin.
One possible plot could be a moment of comfort. Maybe Merlin has had a rough day dealing with magical threats in Camelot. He sits on Arthur's lap, and they have a heart - to - heart talk about their friendship and the future of Camelot. Arthur, initially surprised, soon realizes Merlin needs this closeness and they end up strengthening their bond.
One possible plot could be a moment of deep friendship. Maybe they are in a private chamber, discussing a serious matter about the kingdom. Merlin, in his eagerness or perhaps to show his loyalty closely, sits on Arthur's lap. They then have an intense conversation where Merlin reveals some hidden knowledge or a plan to save Camelot from an upcoming threat.
The banter between Merlin and Arthur in fanfiction is really interesting. It can range from light - hearted jabs at each other's habits. Merlin might poke fun at Arthur's love for jousting and how he always gets a bit too competitive. Arthur could retort by mentioning Merlin's clumsy attempts at serving him. Their banter also reflects the underlying respect they have for each other despite their different social standings. It's like a friendly sparring that keeps their relationship dynamic.
Merlin would likely be seen as a bit of an enigma at Hogwarts. His magic is different from the norm, so he might be a bit of an outsider at first. But his kind heart and loyalty would soon win over his classmates. Arthur would be the brave and headstrong character, perhaps a bit like a Gryffindor version of his usual self. He'd be eager to learn about combat magic and would probably be a natural leader in group projects or Quidditch teams.
The 'Redemption' trope is also seen in some fanfictions. Maybe Arthur has made some mistakes in the past, and Merlin helps him to redeem himself. Or vice versa. It's a way to explore the characters' growth and development. And then there's the 'Battle Against Evil' trope where they fight side by side against dark forces, which really showcases their bond and loyalty.
I really like 'The Sword in the Stone' as a fanfiction - like take on Merlin and Arthur. It shows Merlin as this wise and mysterious figure guiding Arthur on his journey to become king. There are also some great interactions between the two characters that show the deep bond they share. You can find it in many libraries or online bookstores.
He might be initially startled. Arthur is used to a certain propriety in the court, so having Merlin suddenly on his lap would catch him off - guard. But then, depending on their relationship at that point, he could either laugh it off if they are in a very friendly stage or he might be a bit flustered and ask Merlin to get up if there are other people around.
In Merlin fanfiction, Merlin calls Arthur sire as a sign of respect. In the Arthurian legend and related fictional settings, sire is a term used to address a nobleman or a person of higher status. Merlin, being Arthur's servant and advisor in many versions, uses this term to show his loyalty and deference to Arthur's position as king or prince.