In many fanfictions, Goku's protectiveness of Gohan is shown through his constant presence. He might train Gohan more rigorously to make him stronger so he can defend himself. For example, in some stories, Goku takes Gohan to special training grounds that are hidden from the rest of the world. This not only protects Gohan from potential threats during the training but also hones his skills in a more secluded environment.
Often, Goku will be quick to jump into action whenever Gohan is in danger. He'll use his superior fighting skills and strength to fend off any enemies. It's like he has a sixth sense when it comes to Gohan's well - being. In some fanfictions, Goku even gives up important battles or quests to ensure Gohan is safe, which really shows how much he values his son's safety over his own glory in combat.
Their relationship could be portrayed as more of a brotherly bond. Goku could be like an older brother to Gohan, showing him the ropes of being a Saiyan and having fun adventures together.
One common scenario is when new and powerful enemies emerge. Goku will immediately position himself between Gohan and the threat. He'll use his body as a shield if necessary. Another scenario is when Gohan is training and pushes himself too hard. Goku steps in to make sure he doesn't overexert and get injured. In some fanfictions, when Gohan is exploring new places, Goku follows closely behind to protect him from any unknown dangers.
In some fanfictions, Gohan and Goku might have a series of conversations that open up new levels of understanding between them. Gohan could share his thoughts and feelings about his life and future, and Goku would listen and offer his own insights. This kind of communication can really strengthen their bond.
In such fanfictions, Goku might develop by becoming more of a mentor to Gohan. He could teach Gohan new fighting moves and also how to control his emotions better during battles.
In certain fanfictions, Goku's depression is manifested in his dreams. He could have nightmares about his failures or the destruction he couldn't prevent. These dreams haunt him during his waking hours, making him more withdrawn and less likely to engage in his normal activities.
In a Gohan x Goku fanfic, their relationship can be delved into by creating scenarios where they have to rely on each other completely. For example, if they are in a situation where Goku's strength and Gohan's intelligence are both required to escape. Their different personalities can also be highlighted. Goku's carefree nature contrasted with Gohan's more studious and responsible side. And of course, flashbacks to Gohan's childhood and how Goku's presence or absence affected him can add depth to their relationship.
In some fanfictions, Gohan and Videl's relationship might be deepened. The 'lemon' aspect, if not in an inappropriate way, could symbolize something sweet and special between them. Maybe it represents a new phase in their relationship, like a honeymoon - like period full of love and new experiences.
You can focus on their emotional bond. For example, show how Goku's pride in Gohan's growth and achievements affects their relationship. It could be about Gohan seeking Goku's approval and Goku being there to give it wholeheartedly.
One possible interaction is that Bardock could spar with Goku and Gohan. He'd test their limits and see how much they've learned about fighting. Another could be Bardock sharing stories of Planet Vegeta with them, which would be really interesting for Goku and Gohan to hear.
Goku would be a mix of angry and worried. His Saiyan blood would make him want to rush into battle with Raditz right away. But he also knows how dangerous Raditz is, so he might first try to gather some allies, like Piccolo. He'd be constantly thinking about Gohan and how to rescue him as quickly as possible.