Some Skully X Flowey fluff to show the start of their relationship.
This is actually canon to the series storyline and is years after Skully first met him. To sort of give the appropriate amount of backstory to this, Skully and a few friends went through the plot of Undertale and spared Flowey. After saving Asriel by each of them sharing a third of their soul (Skully, Isis, and Henry), Flowey was forced to take someone else's soul (Chara's) in order to keep surviving, but in order to make sure he didn't go crazy with power again, he was left with Sans, who tormented him for over ten years with puns and the like. When they came to visit, Flowey was given back to Skully after he insisted on getting away from Sans.

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“Ugh! Shut up already!” Flowey said in his high-pitch voice from his flower pot. “You’re so annoying!” he complained, twitching his eyes as he stared at Skully.
Skully rolled his eyes and paused his game. “What’s your deal? You stole Chara’s soul so you wouldn’t die, but you complain about living despite me having Sans spare you and take care of you… And you’re miserable staying in anybody else’s room except mine, but in mine, you can’t stand me.”
Flowey listened while he talked, but turned away and folded his leaves. “Maybe I’m just miserable and want everyone else to be miserable too.”
“That’s not is, though, is it?” the man asked knowingly. “You… prefer my company, don’t you?”
Those words seemed to anger the plant demon as he turned around, fuming. “I HATE YOU!” he shouted at the top of his lungs, which came out as a distorted, high, shrill yell. Though, after he said that, he appear to regret his own words and looked down. “I just use you, okay? I can turn back into my other form and take over this world any time I want!”
“Well…” Skully said softly, with a sigh, as he picked up Flowey’s pot. “If you really think you can and hate me that much, I don’t want to keep you…” he said softly, walking outside and sitting on the ground. “If you really want to be free, I don’t want to be the reason you’re miserable… So… here.” he said, scooping Flowey out of the pot and digging a shallow hole in the dirt before setting him down inside. “There… You’re free to go anywhere you want.”
Flowey looked a bit surprised for a moment, looking around and getting a feel for his free reign again. “You’re setting me free? Just like that? You’re leaving me out here to do anything I want?” he asked, though instead of a maniacal grin, he had an almost sad look.
“Yeah… Believe it or not, as stupid as I may be, I care about you, Flowey…” Skully said softly, soon standing up and turning away. “Goodbye… Flowey.” he said even softer, beginning to walk.
“Skully… Skully…?” Flowey called out softly, tearing up slightly. “Skully!” he shouted louder, a thicker vine lashing out from the ground and wrapping around his arm, though the thorns had retracted on the vine where it wrapped around him.
Skully noticed the vine holding him from walking any further and looked back to see what the demon was calling him for. “Hmm?”
“Skully…” Flowey said softly, his grip tightening slightly as he gave a gentle tug to lead him back. “Please don’t leave me again…” he said, a few drops sliding off of his petals. “I don’t like being around everyone else… But I don’t like being too far from you…” he said, seeming to blush softly as he averted his eyes. “I’m miserable away from you and I’m miserable with you, but that’s only because I see how happy you are sometimes and… And…” he trailed off, looking up as Skully got on his knees and hugged him softly. He gave a gentle gasp as the motion was done to him, soon causing more vines to erupt from the earth and wrap around various areas on Skully and squeezing in response. “I… I-I…” he started to say, but was unable to finish his sentence, instead shifting to his Omega Flowey form and using his thick, bushy arms to hold him close in a more anthropomorphic form.
Skully was surprised by all the affection or even the idea of Flowey having a heart. but he welcomed it; especially more in the form change, since it was a little scarier. “I love you, too, Flowey…” he said in response, having figured that’s what the flower demon was trying to say.
Omega Flowey only smiled softly in response; not that Skully could see it on his screen. He blushed softly and his wicked smile softened to a happy grin, but he tried not to show it. “Anyone who falls for a flower or a demon is just stupid…” he said, giving light chuckle.
“Maybe I am stupid…” Skully replied, looking up at the screen. “But everyone needs someone, Flowey.” he added, noticing Flowey’s tsundere type response of rolling his eyes and averting them.
While Omega Flowey found it cheesy and even somewhat moronic, he appreciated the thought and looked around to make sure nobody else could see his next move. He brought his screen close to Skully’s face and kissed his lips with his bigger mouth, it feeling much like a glossed over skin with a light static feeling. “I… lo-… like… You better get used to sleeping outside, because I like it out here now.”
“Flowey…” Skully aid softly, finding himself blushing for once. He hadn’t expected Omega Flowey to be capable of kissing, but was pleasantly surprised to find the screen capable of making contact with him. Not to mention that he had been kissed at all. “I know, Flowey; you love me, too.”
Omega Flowey blushed a lot harder and muttered something under hie breath as he dropped Skully onto the ground, albeit fairly gently. “Don’t be so cocky about it.” he grumbled, though, he glanced around a little bit and gently ran his claws through the man’s hair. “And don’t ever leave me with that annoying skeleton, Sans, again.” he said, his eyes brightening slightly as he grinned. “Right by your side is where I belong… Tormenting you all day and making you question whether or not I’ll turn on you~”
Skully chuckled a little and blushed. “Oh, Flowey, you won’t turn on me… I know.” he stated, looking up at the screen with a sincere smile. “You care about me, even if you won’t admit it… And you love me, too.” he teased, softly grabbing the red claws. “Hey… I care about you, too, Flowey… And I love you, too.” he said, a slight sadness to his eyes as he spoke those words. “So… Please don’t be sad, okay? I promise I’m not going anywhere again.”
There was an awkward, silent tension between the two as Omega Flowey’s smile softened down to a slight neutral expression. Even that faltered to an almost saddened look, which he immediately tried to hide. “…I promise I’m not going anywhere, either…” he spoke softly. He scooped Skully back up and held him against his body firmly, his screen going staticky for a moment before it showed a saddened smile. “And I…” he started to say, soon blushing fairly hard. “I… love you, Skully…” he finally said, exhaling sharply. “And nobody lays a finger on you or I kill them, okay?”
“Alright, Flowey…” Skully replied, kissing the bottom of the screen, gaining a blank expression from the monster. “I believe you.”
“You idiot…” Omega Flowey replied, smirking slightly as he slowly reverted back to his flower form. “Now, get me a pot so I can come inside with you… The sun is too bright.”
“Uh-huh… That’s the only reason.” Skully replied jokingly, grabbing the same pot as before. “I’ll cuddle you, promise.”
Flowey blushed softly, uprooting himself and getting back into the pot, covering himself back up with soil. “Just take me inside…”
“Alright, Flowey.” Skully replied, standing back up and beginning to walk. “I’m glad you’re still here.”
The demon only blushed softly, speechless as smaller vines griped Skully by the back of his head and pulled him in for another kiss, the pets closing around his face to obscure anyone’s view. “I’m glad you’re still here, too…”