There shouldn't be. Our society values healthy, consensual and proper relationships. A story like this goes against the basic values of respect, propriety and legality in human relationships.
The story could be about a mom and her son having a wonderful day at the sea. Maybe they are building sandcastles, looking for seashells or just enjoying the beautiful view of the ocean. It could also be a story of how they face some challenges at the sea, like a sudden storm, and how they overcome it together.
There was this mom and son who planned a date at the local library. The son loved books. They entered the library and the mom let the son pick out a bunch of books. Then they found a quiet corner. The mom read aloud to her son from one of the books. They spent hours there, just沉浸在书的世界里 (immersed in the world of books). It was a very special and educational date for them.
One possible story could be about a mystery that unfolds between a mom and son in a house. Maybe there's a hidden room in the house that the son discovers and he and his mom try to figure out what it was used for in the past. It could be something related to the family's history, like an old attic filled with letters and photos from generations ago.
The story could be that there is a locked chest in the house. The mom and son are curious about what's inside. They search for the key everywhere. Eventually, they find it hidden in an old book. Inside the chest, they find a family heirloom with a note that tells a story about their ancestors.