All the pretty girls can't measure to you

He wasn't. He couldn't be.
Louis was humping his leg.
Maybe he was sleeping, Harry's thoughts spun wildly, having a dirty dream. But Harry knew Louis up and down, the patterns of his breathing, the tension in his muscles - this wasn't sleeping Louis. As if to confirm Harry's thoughts, Louis gripped him slightly and unmistakably ground his hips.
A soft moan escaped Harry's lips.
Louis stilled. Harry held his breath.
No no no please don't stop, God.
Louis' hands traveled up his body lightly, the barely there touch making him hiss.
"'S this ok?" Louis' voice sounded uncertain, hesitant, like his fingers delicately tracing Harry's spine.

Or:
A whole lot of cute fluffiness takes a horrifying descent into hardcore godless smut. But it's ok though cuz it's Louis and Harry and they're adorable little cupcakes who love each other very much.