It all started when Gray's apartment complex was fumigated for an insect problem they'd been having. He had been told that he couldn't sleep there that night, so he'd need to find someone to stay with. He was on his last portion of jewel, getting ready to take another job, so he couldn't afford to stay in a hotel for the night. Erza lived in an all-girls' dorm and Lucy's apartment was way too small for a second person, so he had to go with the option he dreaded most - staying with Natsu.

"You seriously don't have enough money to stay someplace else?" Natsu complained.

"Well, not since somebody caused us all to have to give half our payments up in damages," Gray shot back. "It's not like I'm enjoying this, either."

There was a moment of silence until Natsu declared suddenly, "Ok. We fight for who gets the hammock and who gets the floor."

"What?"

"You're the guest! You play by my rules!"

Enraged by Natsu's lack of hospitality, Gray showed his consent by tackling Natsu onto the ground. 20 minutes later, with frost bitten walls and singed carpets, Gray was victorious through his sheer annoyance toward the pinket.

When night had fell and all the candles were put out, Natsu and Gray both settled into their respective places in the room. Natsu was just about ready to plunge into dreamland, eyes heavy with sleep, until he heard a slight moan come from above him.

Damn, I must have really done a number on Gray, Natsu thought triumphantly. I knew he couldn't handle me. I'm still the stronger of the two of us!

Natsu's ego trip was interrupted by a second moan, much louder and higher pitched this time. He started to wonder if he should wake Gray up if hurt that badly. This decision solidified for a much different reason when he heard the third thing to come out of the ice mage's mouth:

"Harder, Natsu!"

Fist engulfed in flames, Natsu instinctively bounded up off the floor and punched Gray in the chest on the hammock. Startled, Gray flailed on the hammock and let out a slight scream.

"What the hell, Natsu!?" Gray yelled angrily as soon as he had fully shaken himself from sleep. Natsu quickly fell back down onto the floor and covered his face with his scarf, feeling his cheeks get hot.

"Uh, you keep talking in your sleep and it's getting damn annoying! Cut it out!" Natsu stammered, embarrassment now replacing his initial anger. Gray's eyes widened ever so slightly, giving the tacit indication that he was slowly realizing what Natsu may have heard. After a second of pause, Gray unconfidently spat back,

"Shut up and let me sleep, ash-for-brains."

Within a few minutes, Gray was fast asleep once again. Natsu, unable to fall asleep right away from the shock, decided to have a bit of fun.

"Don't stop, Gray!" Natsu panted quietly. Gray responded with a moan. Natsu kept this up until Gray nearly screamed in pleasure and proceeded to calm down. When his breathing returned to normal, Natsu barely picked up what Gray muttered under his breath, even with his sharp hearing:

"I love you, flame-brain."

"I love you, too," Natsu whispered passionately, the banter so natural that Natsu didn't even realize what he had said until after he'd uttered it.

To this day, Natsu will still make over-exaggerated noises whenever his newfound lover gets sleepy, earning him a customary punch in the stomach and kiss on the forehead.