"Is that a tattoo, pretty boy?" Morgan asked, the corners of his lips upturned with unspoken mirth. He had dragged the younger man to a self defense class and they had showered in the locker room afterward, and the inked skin was only barely visible on Reid's hip bone, peeking out of the towel wrapped around his waist.

Spencer spun around at the question, his hair hanging in his face in dark tendrils. "Uh, yeah, it is," he commented softly, face flushed. He tugged awkwardly at the towel, trying to get it to stay higher on his hip, to cover the ink.

"I guess Emily wasn't the only rebel in high school, eh?" Morgan teased lightly, pulling a dark v-neck over his head. Though lighthearted, Morgan was genuinely surprised, he certainly hadn't pegged Spencer for the tattoo type.

"I got it when Emily and I got engaged, actually," Spencer replied. "She got her stone, I got a tattoo, its Euler's Identity," he explained, "its widely regarded as the most beautiful formula in mathematics," he shrugged, spinning the combination dial on his locker.

"Math is beautiful?" Morgan scoffed, the concept was foreign to him, but then again, most math was, he had really only gotten past basic algebra and trigonometry in high school. "That's two ridiculous things for the day, if I weren't so sore from that class, I'd think I was dreaming."

"Euler's Identity utilizes three basic arithmetic operations only once and it links five fundamental constants, the additive identity, the multiplicative identity, pi, the number 'e' and the number 'i.' The beauty of the formula lies in its simplicity," Reid explained further, though Morgan didn't seem to be catching a word of it.

"Last I knew, pie was a food and e and I were letters, not numbers," Morgan replied with a laugh, throwing some things in his gym bag. "You should save that math crap for someone else, I barely scraped through algebra with a b minus."

Reid just nodded, and got ready to leave.

hr

"Morgan asked about my tattoo," Spencer spoke with an amused tone as he dropped onto the queen sized bed next to Emily, giving her a peck on the cheek before letting his head sink into the pillow. She was on his side of the bed, to his chagrin. She had demanded that they switch sides because she wanted to be closer to the window, but she insisted on migrating to his side every opportunity she found.

"Oh really," Emily grinned, "what'd you tell him?" She asked, rolling onto her side, absentmindedly bringing a hand down to his hip to drag a thumb over the inked skin. "Did he think it was your manufacturing code?" She teased lightly, and for some reason, it didn't sting him the way Morgan's teasing occasionally did.

"I told him that I got it when we got engaged, and that it was the most beautiful mathematical equation," Spencer replied lazily, tiny goosebumps raising along his sides as her cold hands brushed over his skin. "I didn't think it was necessary to mention that the e doesn't stand for Euler in this equation, it stands for Emily, and that's why its beautiful," he smiled at her, tucking a strand of hair behind her ear.

"You're so corny, Doctor Reid," Emily laughed lightly. "But I love this tattoo," she added, hand tugging at the waistband of his khakis. "How did Morgan see it, anyways?" Emily frowned, the tattoo was rather low on his torso, nearly dangerously so, but that had been intentional, he wanted to be able to conceal it for the FBI.

"Locker room at the gym," he explained with a shrug, brushing a soft kiss against Emily's neck. "It's not my tattoo I'm worried about him seeing," he nipped her collar bone gently, "it's yours." He trailed his fingers down her side, soft and nimble, resting them over her hip, the same place he had his tattoo, she had the words, "So it goes," inked onto her creamy skin.

"Don't worry," she replied with a smile, tilting her chin slightly to allow him better access, "I don't ever plan on letting Morgan see my tattoo. I imagine that would be rather awkward," she couldn't help but giggle slightly, picturing the stunned look that she knew he'd have.

"Or anybody else," Spencer added, dragging his teeth across the pale skin on her neck as he lifted her red tank top. Emily's eyes fluttered shut; it would have been unnoticeable to anybody else, but she knew him well enough to know that he was feeling possessive, and though she didn't like to be treated like a piece of meat, like previous boyfriends had, she couldn't help but smile slightly to herself.

"Or anybody else," she confirmed quietly. He didn't need an answer, Spencer knew that she would never even consider anybody else, but there was no harm in reassuring him once in a while. "Except maybe Rossi..." she trailed off with a smirk, there wasn't any harm in playing with his possessiveness either.

"I don't think so," he whispered, mouth pressed against her ear. Spencer took her earlobe between his teeth. Morgan always laughed at his statistics, but really they could come in handy, especially when it meant knowing that nearly ninety percent of women found ears to be a sweet spot.

"Okay," was all she managed to mutter, fumbling with the button on his khakis. He caught her wrists, stopping her from going any farther. He guided her hands above her head, to rest on the pillow with a warning look that clearly said, 'leave them there.' Emily was more than happy to oblige, her dilated eyes wandering over Spencer's body, her heart beating faster than normal, and she tried to remember which chemicals exactly were doing that to her. Spencer would tell her of course, if she asked, but she couldn't get the words out.

"Not yet," he chastised, dropping lower on her body to press a soft kiss against the black lettering. "So it goes."