"Bruises on your thighs like my fingerprints" from Centuries by Fall Out Boy!
And also smutty. Not for the kiddos, this one.
Natsu grumbled as a shaft of sunlight waned through the curtains onto his eyes. Not wanting to fully wake up quite yet, Natsu buried his head further into the pillow he was sleeping on, before bonking foreheads with the previously asleep wife in his arms.
"Owwww, Natsu, what are you doing…?" Lucy whined sleepily, snuggling into him and his warmth, not wanting to get up. "Ughh," she complained as her senses came to her. "We were too rough last night. My legs hurt."
Natsu smirked as he kissed her neck where his lips were already perched. "I know a way to make you feel better," he teased.
Lucy rolled her eyes, but leaned into his touches. "And how, exactly, is more sex supposed to make my sore, aching body feel better?"
Natsu caressed her side, fingers tapping lightly along her hip. "Because if you're screaming in pleasure, you're not gonna be focusing on your soreness." Lucy scoffed at his logic, but pushed the blankets off to the side and let Natsu crawl on top of her nonetheless. "And besides, I wasn't talking about just regular ol' sex," he continued, giving Lucy a saucy smirk as he moved down her body, leaving kisses and hickeys in his wake. "I figured I'd go down on you."
Lucy let out a moan as he gave a careful lick up her already weeping slit. "Nngh, Natsu…" she looked down to him, fingers already fisting in his hair. "Natsu, I've got bruises on my thighs!" she cried when she noticed the dark purple spots dotting her skin.
Natsu chuckled, lining his fingers up with the marks. "They're just like my fingerprints," he remarked, before adjusting his hold on her legs and starting his work to make her scream.