Real life kisses aren't separate events that start and stop at clearly defined points. They are a progression of intensity, and the sensations experienced and thoughts that arise are particular to the players. Because of that, a kissing scene should be deeply revealing, without stating every last thing about the couple. Use both senses and spaces to invoke tension.
"She stood, legs braced to counter the pitch of the hill, the frigid air swirling around her, the sky black as anthracite, each star a hard chip of broken glass ablaze in white light. They were crowded against each other on their small outcropping, the heavy telescope on its tripod shared between them, their arms protected by thick parkas, touching from shoulder to elbow.
Her arm, where it pressed against his, burned. She shivered, cold penetrating all the rest of her. She thought about the stars - the ones shooting across the night trailing arcs of light, the ones too far or too dark to see.
"Your turn." He shifted slightly and for a moment she wavered off-balance. Then his arm went around her, drawing her back from the edge, and his face bent to meet hers as she looked up, startled. Two eyes, black as night, glinting with reflected stars, full lips a heartbeat away, no distance at all.
Those lips met hers and her world exploded into shards of molten light. His grip tightened across her shoulders, pulling her into him, pressing himself into her. She knew his other hand steadied the scope, knew the pull of his constellations, his star world. She didn't care. Her hungry mouth melded into his, the arctic chill forgotten. The tip of his tongue brushed her lips, insisted, and she opened to let him in, welcomed the urgent thrusting that sent a wildfire of searing flames racing through her body.
She clung to him in some alternative universe of longing.
Held on for her life.
A wave of darkness washed over her and she shuddered and pushed him away.
There were inches between them on their precarious perch. There may as well have been worlds.
"We're going to miss something." For the space of a held breath there was silence. Then his voice floated over to her from a distant galaxy.
"We already have."