A setting could be at a celebration. After achieving a great victory, everyone is in a joyous mood. Gamora and Nebula find themselves drawn to each other in the midst of the festivities. The bright lights and happy atmosphere create a contrast to their usually dark and complex relationship, and they kiss. Or it could be in a medical bay, where one of them is injured, and the worry and relief lead to a moment of passion.
In some fanfictions, the setting is during a rescue mission. Gamora has been captured, and Nebula comes to save her. In the midst of the chaos and danger, they share a kiss. It could also be in a place full of memories, like their childhood home (if they have one in the fanfiction). Returning to a place filled with their past could stir up emotions and lead to the kiss.
One common setting is on a spaceship. They could be in a quiet corner of the ship, away from the rest of the crew. Maybe they've just survived a dangerous battle, and the adrenaline rush leads to the kiss. Another setting could be on a desolate planet. They're alone, and the isolation makes them confront their feelings for each other, resulting in the kiss.
I'm not really into the 'lemon' genre which often implies inappropriate content. However, you can try looking on fanfiction platforms like Archive of Our Own. They have a wide range of fanfictions about Gamora and Nebula that focus on their relationship in more appropriate ways, like their sisterly bond and how they support each other through their shared traumas.
One great 'Shadow Kiss Nebula' fanfiction could be one that focuses on the unique relationships between the characters. It might explore the backstories that are only hinted at in the original concept, like how the different species in the Nebula interact on a more personal level.
One setting might be in a secret underground lair. They've just defeated some bad guys and in the heat of the moment, they share a kiss. There are strange machines and artifacts all around them. It gives a sense of adventure and danger. Also, they could kiss in a beautiful garden full of exotic flowers. The colors and scents of the flowers add to the romantic mood, and there might be little fairies or magical creatures flitting about, making it an even more magical place for their kiss.
One setting could be at a school dance. The lights are low, the music is playing softly, and Ralph and Caitlin find themselves alone on the dance floor. They look into each other's eyes and share a tender kiss.
An interesting setting could be in a dangerous situation. For example, Naruto is in the middle of a battle and is about to be defeated. Kushina appears (maybe as a spirit or some other form) and gives him a kiss that empowers him, allowing him to turn the tides of the battle.
Another setting might be during a festival. There are bright lights, happy people all around, and a festive mood in the air. Yato and Bishamon could get caught up in the excitement and find themselves in a secluded corner where they kiss. The noise and celebration of the festival contrast with the intimate moment between them.
Another setting could be on a beach. The sun is setting, painting the sky in beautiful hues of orange and pink. Akito and Sana are taking a walk along the shore. The gentle sound of the waves crashing is the only noise. Akito stops Sana, looks into her eyes, and kisses her. The beach setting adds a sense of romance and tranquility to the moment.
Since 'lemon' content involves inappropriate themes, it's not something that should be promoted. However, in general non - 'lemon' fanfictions about Gamora and Nebula often explore themes of redemption, forgiveness, and family. Nebula's journey to find acceptance and Gamora's role in that can be a common theme.
A high school setting would be a common one. They could be in the school cafeteria during lunch break. Maybe there's a school dance coming up and they are both on the committee to organize it. Tensions and feelings build up as they work together, and finally, they kiss in the empty cafeteria after everyone has left for the day.
One common setting is a beautiful, peaceful balcony. The twinkling stars above and the gentle breeze create a romantic atmosphere for their first kiss. Another setting could be in a dimly - lit room, where they are having a deep conversation and the moment just feels right for that kiss. Also, some fanfictions might have their first kiss in a natural setting like a forest, with the sounds of nature as a backdrop.