Reid and Morgan arrived at the office early. Everyone else had yet to arrive. Knowing that Reid liked to come to work in the wee hours of the morning, Morgan had decided to catch the younger agent when he knew he'd be alone.
"God, Reid, it's four in the morning. What are you doing here?"
"I could ask the same of you, actually. I thought you had a social life."
"Let daddy do the questioning, kid. You just answer."
"I was working on finding the last digit of pi."
Morgan grinned. "Wanna help me find a place for my digits?"
Reid glanced at Morgan before looking back down at his notes. "I don't understand," he said, before scratching them out with his pen in frustration.
Morgan laughed and punched him in the shoulder. "I'm just kidding," he reassured lightly. "Hey," Morgan said, growing more serious again. "I think I figured out the last two digits of pi, though."
Reid cast a doubtful glance upon his partner. "Really, Morgan? What?"
"Sixty-nine."
"Sixty-nine," Reid repeated, rolling the number around experimentally on his tongue and most definitely making Morgan's pants tighten. "Can you show me how you got that?"
"No problem, pretty boy. But you'll have to strip first."
"Morgan, I don't understand how my disrobing would be conducive to your explanation."
Morgan held up his hands in a placating manner. "I know it might hurt to hear this, Reid, but there is no such thing as Santa Claus. Also, there was a course I took back in the day that you never even enrolled in. Trust me when I say you have some catching up to do. Let me offer you a remedial course. Now subtract the clothes from this equation."
Reid shed a single tear. "But I've never been behind in anything!" And with much determination, he removed each article of clothing until he was simply standing in his birthday suit.
Morgan, on the other hand, expertly shed his own attire and moved in close to his prey. "You're the sub and I'm the unsub," he explained.
"What?!" Reid exclaimed, horrified.
"Nevermind. Think of it this way: we're like a fraction. You're the denominator and I'm the numerator. Get it?"
"But," Reid objected, "Zero can't be in the denominator. That'll make it undefined."
To that, Morgan replied, "This is undefined, baby."
Just then, Hotch entered the office, spotted his two naked agents, and walked back out again.
"Wait!" Morgan called after him. "I was just teaching Reid some physics!"
"But I've already taken physics!" Reid pouted.