One popular storyline could be Sonic finally realizing his true feelings for Amy during a dangerous adventure. They share a kiss as a sign of their newfound closeness. Another might be a time - travel plot where Amy goes back in time and Sonic, seeing her in a different light, kisses her. And there could also be a story where they get trapped in a magical realm and the kiss is a way to break a spell.
Well, in some fanfictions, the kiss between Sonic and Amy might happen after Sonic saves Amy from a really tough situation. It shows his deep care for her. There are also those stories where Amy takes the initiative. For example, she might confess her love in a very heartfelt way and then they kiss. Sometimes, the kiss is just a part of a series of events that lead to a stronger relationship between them in the fanfiction world.
In a lot of Sonic and Amy kiss fanfictions, the storylines often revolve around emotional growth. Sonic, who is usually so focused on speed and adventure, starts to notice the little things about Amy. Maybe it's how she always believes in him no matter what. This realization could lead to a tender moment and a kiss. Another common plot is when they face a mutual enemy. Working together closely, the bond between them deepens and results in a kiss that symbolizes their unity against the foe.