@valiisi liked for a writing starter!
((I googled your username and got a "horse pump" so I chose to go with softcore Satan. Hope you don't mind and lovely alliteration by the way.))
Satan's face twitched and moved uncomfortably as he began blushing at what he was seeing. He normally wouldn't act this way, more depraved things happened in hell and he never batted an eye at any of it. Somehow, these soft caresses and gentle kisses were all it took to make the most evil being God ever created squirm. This made his anger flare up as he tried to scowl tempted to scream at the demon who sent this foul video. But, he couldn't tear his eyes away from these disgusting creature's playful intimate act.
His resentment for humans ran deep like the halls of hell and hadn't quelled over the countless centuries spent watching them. He never knew what made them more important than some other animal. In many ways, they were so much worse with their genocides against each other, the perverse inhumane way they sought pleasure, and he didn't want to discuss how they treated God's planet. Many humans believed he was the reason so much filth existed in the world when his only real duty was to punish the filth that was already there. One would think that Satan would get used to the vulgar way people went about sex, but he never did. He mostly just became disgusted and desensitized to the casual violence that was so present in "loving" human relationships. He mostly avoided it if possible handing dealing with "that sort of thing" to a lower demon.
Giggles and adoring smiles came from the screen, nothing was really seen just implied but that somehow made it feel more personal. Satan felt like he was watching something not meant for him to see. They clearly actually cared and loved one another creating something...divine. Lucifer shook himself trying to perish the thought of actually finding human relations to be worth his time much less arousing. No, he couldn't admit that, he wouldn't so help him. However, that didn't stop him from watching it and drinking every detail in even if he tried to fake anger. There was no loud smacking of flesh or obnoxious fake moans, it was just two people loving each other and showing it in one of the most physically intimate ways possible.
Once the video was over, he was left alone with himself and his new and aching emotions. They all demanded their own attention, analysis, and thought but he knew that if he did that he might have to admit that he liked one thing about humans. And if he could like one thing what was to stop him from liking other things? His entire crusade to get at God through the disgusting creature that is man would be...No he wasn't going to do that. He forced the emotions down and swallowed the lingering thoughts. He got up from his throne and decided to walk the infinite punishing halls of hell yet again to help clear his mind. He looked back at his phone and the video discreetly saving it...for future reference. Once that was done, he shoved his phone away and returned to his usual disgusting, depraved, and grotesque affairs.