This is my first drabble, I saw the scene from The Long Goodbye and Rodney's 'look' when he overheard the conversation and I thought I'd give it a try. I hope you enjoy!
"Was he lying?" McKay asked.
Sheppard turned, confused. "What?"
"He said, 'He cares for you more than you know'. Was he lying?"
"Look, that's none of your business." Sheppard said defensively.
McKay turned hard, "You need to stop. Stop caring for her, or stop your idiotic kirking."
"Hey now…"
"Don't you see what you're doing to her?" McKay didn't think he was that stupid, "She's one of my only friends and I won't let you keep hurting her."
Sheppard couldn't reply.
"I mean it, STOP, one or the other; or you'll be sorry."
He knew McKay meant it and nodded.