Hinata remembers their first kiss well.
It happened in probably one of the most un-romantic moments, when they were both stressed out of their minds over studying (Oikawa doing double since he was also practically tutoring his boyfriend) and how they miraculously made eye-contact at the right second to spark a heated moment. Hinata remembers how they both slowly leaned in, Hinata practically climbing onto Oikawa's lap, his breathing shaky from nerves but still managing to calmly close his eyes before their lips met gently. The first feel of pressure as their mouths glided against each other didn't last longer than a few milliseconds, but it was enough for Hinata to dive right back in. Hard, quick and eyes scrunched, which lead to poor aim and for his teeth to press against the inside of his lip uncomfortably, their noses to squishing together.
He remembers the small throaty chuckle Oikawa released after the initial shock, which Hinata now figures was due to his terrible kissing skills, it was also his first kiss overall. He remembers how he soon relaxed under Oikawa's ministrations, the brunet cupping his cheeks and tilting his head gently; slowing the kiss, coaxing Hinata to actually move his lips instead of just smushing them against Oikawa's mouth. That's when Hinata realised how nice kissing was, and when he finally realised that the 'magic' the movies showed and the girls in his class talked about was real. Hinata remembers getting confident, starting to crave more of the sweet and warm pressure, and beginning to frantically push back, kissing Oikawa over and over, hands coming up to scrunch desperately in his boyfriend's shirt, hoping it would help keep him grounded so he wouldn't get washed away. He remembers the delicious noise Oikawa gasped against his mouth when Hinata's teeth accidently joined in, which only caused him to take over, nipping gently on Hinata's bottom lip in payback, gaining small whimpers that shocked the red-head as much as it did Oikawa.
Hinata remembers the first moment tongues were introduced, how he jolted slightly when Oikawa lightly licked at his top lip, just grazing the bottom of his teeth before beginning to press forward, Hinata happily widening his mouth and tilting his head even further to open up for Oikawa as much as possible. He remembers the embarrassing noise he let out when Oikawa began to lap at the inside of his mouth, small electric shocks of pleasure coursing down his spine, he remembers the overwhelming taste of Oikawa when he sometimes breathed into Hinata's mouth, how he tasted sweet and fresh from the smoothies they had made earlier, with a coating of pure warmth. How Hinata soon joined in, tongue melding and sliding along Oikawa's own, craving that taste and pressure, leading to the kiss becoming more open-mouthed and messy than secluded and private, his ears forgetting the gross, wet sounds they were making and instead picking up each and every harsh breath and airy gasp Oikawa made, making him want to hear more.
Hinata remembers when the kiss slowed naturally, each lick of their tongues and press of their lips becoming prolonged and savoured, wanting to memorise the shape of each other's mouths, the texture of each other's lips and the sound of each other's breath, as if it was their last. He remembers when they finally pulled away, feeling light-headed and hot, looking at the state of each other through hazy and lidded eyes, seeing each other flushed and glowing, hair and clothes mussed from unknowingly wandering hands. He remembers them laughing, thin from lack of oxygen and slightly embarrassed, before cradling each other and soaking in their happiness.
Hinata remembers their first kiss well, and enjoys the fact that the hundreds after and the inevitable ones in the future will still feel exactly the same.