One way to make it more engaging is to create a build - up. Don't just jump straight to the spanking. Show the events that lead to it, like Lucy's repeated misbehavior and the warnings she received. Also, include some internal dialogue for Lucy. Let the readers know what she's thinking about the situation. And adding some humor or irony to the story can also draw readers in. For instance, if Lucy thought she could get away with something but then gets spanked in a really unexpected way.
One way is to develop complex characters. Give the abuser a backstory that makes their actions somewhat understandable, not justifying but adding depth. For Ichigo, show his internal struggle in detail. Another way is to add a lot of action. Maybe Ichigo tries to fight back in creative ways. Also, use vivid descriptions of the settings where the abuse takes place to create an atmosphere.
Well, perhaps a theme of power dynamics. If Lucy gets spanked, it could show who has the power in the relationship, whether it's a parental figure, a partner, or someone else. Also, redemption could be a theme. Maybe Lucy did something wrong and the spanking is part of her journey to make amends.
Involving other characters in an interesting way can make it more engaging. Maybe there's a character who is trying to understand what the baby is experiencing during hypnosis. They could be an older sibling or a parent. Their reactions and attempts to communicate with the baby can add depth to the story. Also, creating a sense of mystery around the hypnosis itself, like not revealing all at once why the baby was hypnotized or what the full extent of its effects are, can keep the readers hooked.
Adding a lot of vivid descriptions. For example, if the story is set in a forest, describe the lush greenery, the sounds of the animals, and the smell of the damp earth. This makes the setting more real for the readers.
Adding vivid descriptions of the emotions involved can make it more engaging. For example, describe the mother's fear, the father's anxiety.
To make a 'Naruto is heartbroken' fanfiction more engaging, focus on his emotions deeply. Describe how his heartbreak affects his daily life, like he might stop eating or training. Also, add some flashbacks to happier times to contrast with his current state.
By developing strong characters. Make Gamzee's character multi - dimensional, with his own hopes, fears and quirks. Also, create interesting antagonists if there are any involved in the abuse situation.
The meeting can be made more dramatic by having it during a battle. For example, Lucy could be in trouble, surrounded by powerful enemies, and just when she thinks all is lost, Natsu bursts onto the scene, his flames blazing. The contrast between Lucy's moment of despair and Natsu's sudden, heroic entrance would create a lot of drama.
Add some mystery. For example, after the kiss, Merlin starts to have strange visions related to Arthur's future. This will keep the readers hooked as they try to figure out what these visions mean and how they are related to the kiss.
Add some mystery. For example, the mother could have a secret past that is slowly revealed throughout the story and that somehow ties into her love for her child. This keeps the readers hooked.