His little experiment (Senku X reader)

Dancing under the Stars

You and Senku finally returned to your work after Gen "discharged" you from your little break. It's been a month However, even after returning, you and Senku were never the same. Senku's interaction with the rest of the team is beginning to be a little more friendly then irritated.
Chrome already knew about your guys' little secret after a week of your return to the lab. He pestered you and Gen about what happened and eventually you gave in. You didn't give him all the details obviously, but enough to know that you and the other scientist were in love. On certain occasions, Chrome would pretend to flirt with you in front of Senku just to piss him off for fun. Senku would respond with either a death glare or if things were really heated, he'd walk over to Chrome and you and grab you and pull you behind him. He'd say the same thing every time, "Hey, stay away from my lab partner or you'll be my next test subject."
Today was a little different, Chrome decided to take it a little farther. Senku did his usual threat and started to walk away, pulling you with him while holding your hand. Then chrome responded with, "next test subject? What? Are you already bored of "your little experiment," Y/N over there?"
To your surprise, Senku didn't have as much as a reaction as your expected, instead he responded with, "Chrome, kindly remove yourself from the lab for a moment." Chrome looked at you for what he should do. You nodded, indicating him to leave the lab, which he did so.
Once everyone was gone, you turned around to see Senku at his desk writing notes.
"Hey Senku, is everything ok?"
He didn't respond.
"Senku please look at me..."
No response.
Chrome and you knew that last comment kinda hurt Senku so you weren't gonna stop till you knew he was ok. You walked behind him and rested your hand on his shoulder, trying to comfort him a little.
"Hey, it's ok, Chrome was just messing with you. He didn't actually mean what he said. You know that."
You felt his hand start to wrap around your waist.
"Yeah... I know... I just want you to know that I'll never get "bored" or "tired" of you, Y/N. Your the love of my life and I want you to stay by my side, forever."
Senku responded, he then slowly sat up and pulled you into his lap. You let him, he let out a sigh that rolled into a very deep hum, almost like a purr or growl, as he held you and nuzzled into your neck. You brushed your fingers through his hair.

Time went by in your precious moment with your chief. After a while Senku pulled away and gently caressed your face.
*sigh* "your amazing" the scientist said
In that moment, he pulled you in for a long a sweet kiss. You traced his shoulder to his neck with your hand. You felt the scars and permanent marks on his neck, along with the recent ones, all left by you. He never left a truly lasting mark on you, he was always so gentle with you. It wasn't something that he was for everyone, he was rather brash and frank with the rest of the team. Though he still was always careful around you.
Occasionally, when no one was looking, Senku would grab your hand and land a kiss on it before the others saw. It was your typical "enemy of the world, gentlemen for his partner" scenario.
When the lab was empty and Senku wasn't feeling well, he'd walk over to you and grab your waist, burying his face in your chest. He didn't quite care for personal space but you didn't mind. Anyone else, when it came to personal space, Senku didn't hesitate to tell them to back off. One of his favorite things is when he's working and you come up from behind him. You'd wrap your hands around his waist and hug him from behind. Sometimes while Senku was pulling all nighters in the lab, you'd make your way to the lab at night to see him. Senku would be writing at his work table at the end of the room in a corner. When he noticed your presence he'd say the same thing everytime, "Come to retrieve me have you? Heh, c'mere Y/N."
You'd wander over, very sleepy, and rather sit in his lap or, you'd sit behind him and wrap your arms around him and rest your head on his back. Senku thought it was cute either way, especially when you'd fall asleep in his arms. He also remembered how much you loved music in his and your time. Sometimes you'd hear him hum or softly sing some of your guys' favorite songs to listen too. Over time, Senku eventually became a fairly well singer and if you wanted to, he could probably bring back some music from 3700 years ago to this village. However, he only sang for you.