River's head was thrown back, one slim thigh pressed to the side of Jayne's head. Her fingers tightened in his hair, and she gave a quiet breathless moan, thrusting her hips up to him again.
There was a commotion going on behind him, but Jayne ignored it in favor of enjoying the feeling of her nails on the back of his head and the taste of her on his tongue. A wall and his callused hand on her hip were the only things holding her upright. His other hand was clutching the fabric of one of those damn liquid dresses she liked so much, keeping it pulled way up, so he could see every single centimeter of her pretty pretty core.
Her hand in his hair jerked suddenly, and he looked up to see her eyes lazily open, though her hips never stopped their slow grind against his tongue.
"They say," she mused, "that you do not know the proper use of mistletoe."
He smirked, and pressed another open mouth kiss to her shiny little quim. It was Kaylee's own fault for pointing out that they were standing under the stupid plant in the first place, and Mal's for laughing at the idea that Jayne would ever kiss the crazy girl.
Its not like anybody ever specified where the kiss went, after all.