It is dragon's law, that should a dragon lose a battle with another dragon the losing dragon will become the mate of the victorious one. This is true for dragon slayers and pseudo dragon slayers.

ON WITH THE SMUT!!!

Gajeel was in an alley being held up against the wall by Natsu. "What the fuck are you doing Salamander?" Gajeel said with a growl and Natsu smirked. "I'm taking what's mine!"
Natsu's hands coated in flames tore apart Gajeel's shirt. Gajeel cursed and tried to struggle only to feel Natsu's arousal. Gajeel blushed and tried to force Natsu away from him, but found that he couldn't. "Dragon Law?" Gajeel cursed and Natsu smirked and kissed his neck. Gajeel tilted his head back.
"That's right; you lost to me and now your mine." Natsu's warm hands ran over Gajeel's firm body and Gajeel moaned. "No way you can't take me I'm stronger than you, you should be my bitch."
"Oh yeah..." Natsu said and began playing with Gajeel's nipples. Gajeel bucked his hips forward grinding his growing arousal against Natsu's full arousal. Natsu licked Gajeel's left nipple while pinching the right. Gajeel closed his eyes in pleasure. "Now be a good boy and let's drop those pants."
Gajeel's eyes shot open. "Wait...What?" Natsu yanked down Gajeel's pants and his hard cock flipped out into the air. "No underwear Gajeel? Nice!"
"Shut Up!" Gajeel's legs were lifted out of his pants. The now naked Gajeel was flipped around and pressed against the wall. Natsu's warm fingers rubbed Gajeel's back making Gajeel shiver in pleasure. Gajeel heard the rustling of clothes. Gajeel turned his head just to see Natsu's pants and boxers drop.
"No fucking way you're going to put that thing in me."
"Aww so cute don't worry you're a tough guy you can handle it." Gajeel felt a warm finger press against his entrance. Natsu pushed his finger in and Gajeel moaned. "Hot, hot, hot, you damn salamander bastard. "
"Guess a finger's no good, time for plan B." Gajeel felt his cheeks get spread and he then felt a warm breath on his hole. "Wait you're not going to....Ahhh!"
Natsu plunged his wet hot tongue into Gajeel's tight asshole. "Oh you bastard, you fucking perverted bastard!" Gajeel cursed although in truth, he was loving this. His cock was hard and dripping and his body was relaxing getting ready for the monstrous rod that was sure to come.
Gajeel was drooling as the hot tongue probed deeper. 'Damn salamanders and their talented tongues.'
Gajeel found his release as Natsu's hand reached around to stroke his leaking rod. Gajeel's seed splashed onto the wall in front of him. "Well I think you're ready."
Natsu said pulling away and positioning his thick rod at Gajeel's hole. The Iron dragon groaned as he was penetrated by the fire dragon's rod. Inch by Inch Natsu pushed his hungry dragon into Gajeel's tight cave.
"Ha Ha looks who's hard again." Natsu said stroking Gajeel's newly aroused cock. "You must love my cock deep inside you."
Gajeel only growled. Natsu gave a test thrust and Gajeel moaned. Natsu began to play with Gajeel's body. With one hot hand he viciously stroked Gajeel's cock, while his other hand rolled one of Gajeel's nipples between his fingers and earned groans of pleasure. Natsu refused to move and enjoyed Gajeel's clenching heat.
"Damn it Salamander move." Gajeel moaned blushing red.
"Say my name first." Natsu said smirking.
"Fine Natsu please fuck me with that big dick of yours." Natsu obeyed and started pounding into Gajeel never stopping the attention to his nipples and arousal.
"Damn Gajeel your so nice and tight inside." Natsu said licking the shell of Gajeel's ear.
"Ahh shut ahh up, oh fuck there fuck me there."
Natsu made sure to angle his thrusts to hit Gajeel's sweet spot with each thrust. "Glad to see you can be honest with me."
Gajeel ground his teeth but did his best to hide his face. Natsu didn't like that. Gajeel was flipped over his legs up over Natsu's shoulders. Gajeel was now face to face with Natsu and Natsu's arousal went deeper inside him. "Ahh you crazy..."
Gajeel's dark red eyes caught Natsu's and he froze. There was so much fire behind those eyes it was like being consumed in a sea of flames. "Touch yourself Gajeel I wanna see you get off from the pleasure of me fucking you. Show me how much you like it." Natsu said and started driving into Gajeel harder.
"Ah, fine perverted bastard." Gajeel started stroking his arousal and Natsu continued to stare at Gajeel with his passionate eyes. The heat from Natsu's stare made Gajeel's body tingle and he was soon thrown over the edge hard as he was slammed hard against the wall. Natsu drove into him hard and the two dragons came together. Gajeel blew his load all over his body and Natsu came deep inside him.
Natsu went down on his knees with Gajeel still in his arms. Once the two came down from their sex high Gajeel glared at Natsu. "You bastard!" Gajeel threw a punch only to have it caught easily. Natsu kissed Gajeel's fist causing the steel dragon to sigh in defeat.
He slumped against Natsu's body and just inhaled his new lovers scent. Natsu rubbed Gajeel's back. "Don't you dare, think I'm weak."
"I don't."
"I am one of the strongest mages around."
"I know."
"You know Dragon Law is forever binding."
"Yep!" And Natsu hugged him closer and Gajeel felt Natsu's manhood grow inside him. "Perverted dragon slayer!" Gajeel grumbled. "Let's go again!" Natsu said with a kiss.

{ Hope you like the first installment of my random bursts at 3am! }
Signing out,
Metallicana-scale~