The first time they kiss, it's rushed. Not how it should have been. Not how they'd been planning it for months and months. Even Clarke, who kisses him first, is shocked at her own actions. He has no time to reply as Miller is pulling him to follow Kane on the mission, and Clarke whispers, "Stay safe," before he's gone.
The second time they kiss, Clarke is crying. Over the war. Over the stress. Bellamy leans over her, comforting her, and she closes the gap between them without thinking. When he pulls away, neither say anything. That is it.
The third time they kiss, Bellamy narrowly escapes his awaiting death. Clarke throws herself into his arms and their lips connect. A lucky accident. He's warm and intoxicating but she's crying again and he's crying and there are just too many words to say which prioritize before kissing.
The fourth time they kiss, it's not really a kiss. None of them really are. A friendly goodbye turns into a peck on the lips. She apologizes but he just smiles and saunters off, a spring in his step she's never seen before.
The fifth time they kiss, it's Bellamy. Releasing all the pent up, unbridled energy stuck inside him, he leans forwards and kisses her. She takes a moment to kiss back, but when she does, it's desperate. Him, her, thrown together frantically, touching every inch of each other with wild hands, falling onto the floor and not even caring that there's a bed right opposite them.
The sixth time they kiss, she's hovering between life and death. The knife wound on her stomach bleeds too fast for Abby to do anything, and suddenly she's dying and his lips are on hers. He cries a lot. She cries too, and as she slips away, she tells him the one thing that all the kisses had been missing.
"I love you."
There was never a seventh kiss.