No. Writing sexual fanfics about real people is inappropriate and violates their privacy. Tom Holland and Zendaya are actors who should be respected for their professional work rather than being the subjects of such inappropriate fictional content.
Another common theme is 'Secret Relationship'. Given their real - life status as co - stars and the public's interest in their relationship, many fanfictions explore the idea of them secretly dating, trying to keep it from the media and the public eye. This often adds an element of mystery and drama to the stories.
You can write about their characters' adventures in the movies they are in. For example, if they are in a superhero movie, you can write about how their characters team up to fight a new villain.
In the fanfic, the lemon could be a gift from one to the other. Let's say Zendaya gives Tom a lemon - scented bookmark. Tom, being a bit clueless at first, doesn't realize it's a sign of her affection. As he starts to notice little things like how she always looks at him when he uses the bookmark, he begins to understand her feelings. And the lemon - scented bookmark becomes a symbol of their budding relationship.
Fanfiction.net is also a great place to look. There are many talented writers who create stories about them. However, the quality can vary, so you might need to skim through a few to find the ones that suit your taste.