Lucy found it endearing when Natsu got jealous on her behalf; watching guys who rudely invaded her personal space get warded off by an angry dragon was often a highlight when the two were out. She'd have a habit of biting her lip and blushing as heat rushed to her core, the sight of Natsu's broad back as he stood in front of her was an instant delight. His gap moe was intense, sometimes she couldn't believe his personalities could switch so quickly. One second he would be talking about how he couldn't wait to get his hands on some fire chicken and the next to be alerted and angry, holding Lucy back while he scared off some pervert. She'd shiver when the primal instinct seemed to disappear as suddenly as it had risen, curious as Natsu instantly went back to drooling over food in his mind.
Rather than ask him why he behaved so strangely, Lucy took it upon herself to test the water with her dragon partner. She let her guard down when they went out to shop, clothes a little more revealing, and Natsu a little more on edge. She giggled to herself as the dragon slayer twitched whenever a guy got too close to her, eyes calculating just who was a real 'threat' to his partner or not.
They were more than friends, but less than lovers, the boundary wavering between the two more often than not. It gave Lucy the courage to see just how far Natsu would go for her, to see if they would ever say the words she often felt were on the tips of their tongues.
It didn't help when Natsu would climb into bed with her, only to take up more than half the space with himself thrown about, hand smacking her in the face more than once. She would groan and get up, change into something less stuffy before attempting to shove the dragon slayer closer to her wall. She cringed at just how much energy she had to waste on moving him, huffing as she could finally lay down comfortably. Natsu would surprise her by wrapping his arm around her waist, pulling her against his chest, and mumbling a drooly goodnight into her ear.
She expressed her discontent to Cana, who blatantly suggested that she just get on top of him and show the idiot who was boss; not in a million years. Mirajane overheard and said that the girls should go clubbing and drink somewhere other than their guild. Levy and Erza accepted on the grounds of a fun girls night out, even Laki and Kinana dragging Bisca along with them. Juvia seemed to agree only in efforts to make a certain ice mage jealous, who pretended to be oblivious while he listened in on their conversation.
"I don't see why you gotta go out lookin' like that, Luce," Natsu grumbled from his perch on Lucy's couch, the blonde sitting in front of her vanity as she did her makeup.
"Is that a compliment?" She snickered as he threw his head back, glaring slightly at the mini dress she wore. Red, his favorite color.
"You'll be back at ten, right?" He asked anxiously as she stood up, Lucy nodding and grabbing her clutch.
"Yup," She smiled as he pouted, ruffling his hair as she made her way to the door. "I can take care of myself, don't worry."
"I know," He grumbled and stuffed his face into a pillow as she walked out.
Her keys jingled in the lock as she feigned failed attempts to open it. The height of the moon told the world the witching hour had just begun, all according to Lucy's plan. Their party intended to go well past midnight, 10 o'clock never being the time she'd arrive home. She only had a couple of drinks, enough to redden her cheeks and leave the scent of alcohol on her breath. She 'carelessly' spilled half a drink on her, ruffled her pinned up hair, pulled a strap of her dress off, and lazily held her shoes. Her front door creaked open, Lucy stumbling slowly inside, not surprised to see the lights out. She bumped into her couch and table for show, shrieking when Natsu lit his palm from his seat on her bed.
"Jeez, Natsu, why couldn't you have turned on the light?" Lucy wheezed as she pat the wall in search of a switch, her breath hitching at the sight of her partner's golden eyes in the dim lamplight.
"You're late," He lamented, Lucy swallowing thickly but refused to submit so easily.
"We were having a lot of fun, I didn't want to leave early," She hummed as he got up, sniffing the air around her before crinkling his nose in disgust.
"You smell like shitty men," Lucy rose a brow at his rude tone, pushing Natsu away as she pursed her lips.
"So what if I do? We were just dancing." The celestial mage dropped her things and turned to approach her dresser in search of pajamas to change into. She squealed as the dress suddenly caught fire, disappearing into ash in a quick second. "N-Natsu!"
"My scent. Only." Her heart fluttered, hands snaking their way around her form. Lucy shook her head and unlocked his hands, quick to slip a t-shirt over her bare chest. She turned with an annoyed glare, walking past him and towards the bathroom.
"I'm not yours," Words she felt they both needed to hear as she wiped off her makeup and rinsed her mouth, cringing at the sound of Natsu flipping her table over. Loke's key burned against her hip, the mage soothing it with the pads of her fingers as she attempted to go cook her partner down. Lucy was surprised to see his eyes their onyx shade, not even knowing had they'd gotten so bright in the first place.
"Why would you say that?" She cringed at the distress obvious in his eyes, searching her own for an answer.
"We've never told each other otherwise…" Lucy mumbled with a half shrug, breath shallow and body stiff as a lone tear rolled down his cheek. He rushed out the window and into the night, heart dropping as she fell to her knees.
Lucy woke up groggy the next morning, thankful her hangover was light, and the sun was hidden behind a flurry of clouds. She weakly summoned Plue to help bring her medicine and water, cuddling with the shaky white dog as she refused to leave her bed. The rumble of her stomach forced her out of the sheets in the afternoon, mildly munching on buttered bread before running herself a hot bath.
Her stomach twisted with embarrassment and regret, Natsu's seemingly heartbroken look reeling through her mind. Any emotion that didn't pertain to fighting energy or his usual goofiness threw her off. He cried when he lost Igneel; she could safely say that was the only time she saw him break down. Even then he couldn't or wouldn't share what he felt about her night out, Lucy contemplating if it was even worth it to be the one to break the boundary when he so smoothly ran away from her.
Natsu hasn't shown up at the guild either, she learned as Mira served her dinner, the blonde kind of fed up at this point. It was clear what Lucy was hinting at that night, expecting the slayer to outright say that she was his. All the jealousy couldn't have been for show, his dragon coming out as well. She'd seen it erupt in battle before, wild and in a frenzy to protect her.
Lucy was startled to see Natsu as she opened her door, himself equally as he turned quickly to face her. They shared a sympathetic look, both practically tripping over her furniture to wrap one another in a tight hold. Natsu buried his nose in her hair, already desperate after a day apart. It was a silent understanding between them, Lucy not wanting to push for answers. She flushed as he purred softly in her ear, whining for her to let him into her bed like any other night. She nodded, not bothering to change and falling asleep effortlessly in the warmth of his arms.