The first time Marco kissed him, Jean was pretty sure some weird thing was polluting the air, making him hallucinate.
His second thought was that Shadis killed off a few brain cells too many, effectively turning him into a delusional idiot. The third thought could have been "oh shit, Jesus fuck, Marco kissed me!" but Jean was not so sure. It was kind of hard to think when his lips were tingling in such a nice way.
l~*~ l
The second time Marco kissed him was three months after the first one and they were both heavily under the influence of alcohol. Their kiss was messy, sloppy, teeth smashing yet very satisfying.
The next morning, they woke up wrapped up in each other. Peeking into each other's eyes, they smiled slightly, the hangover not letting them realise the position they were in. Thankfully, Armin and Mikasa were a bigger spectacle than them.
Those two were naked and had suspicious marks on their back, neck, chest and hips. Later, Jean remembered the kiss and almost fell off the tree he was perched on.
l~*~ l
The third kiss was magical, gentle yet full of fire. Hands were grasping and pulling, fingers clenching possessively over hips and firm flesh of their buttocks. They were both sober, yet drunk on love.
l~*~l
The last time Marco and Jean kissed was when Marco saved Jean from a leering titan lumbering to the bi-color haired man. It was brief, yet full of life and passion, all of the love they were feeling. Then Marco was dead, eaten in half. And Jean's heart broke that day. He would never hold Marco, never kiss his freckles, tease the gentle man nor feel his arms around him. The pain was almost crippling, but Jean continued to live.
He did promise to Marco, after all.