Seduced by The Snake

Severus' Evil, Evil scheme

Harry did love the idea of Severus' plan, once his fiancé told it to him. Harry would act oblivious, while Severus openly flirted with him and did things that clearly told of interest in the younger man whenever Remus, Sirius or James were looking their way.
So when Severus spotted the nose of a black dog in the shadows of a corner in the potions classroom, he walked up to Harry, whom was sitting at his teacher desk, grading papers, and planted one hand on ech side of Harry on the edge of the desk, leaned in close and pretended to show some inconsistencies and mistakes in the papers, pressing his firm torso up against the Heir's back.
When at dinner, where the four reincarnated adults were welcomed to dine with open arms, Severus would lick his lower lip, looking at Harry with half-lidded eyes, when he spotted James looking at him.

That evening, Harry was patrolling the western side of the castle. Despite their obvious attempts at staying hidden, he knew that the three marauders were following him, probably using the map as well. He could hear their footsteps and even spotted them out of the corner of his eyes now and then. The three were very much out of practice, he thought to himself, but he kept acting oblivious.
Once he reached a remote part of the castle that he and Severus had decided upon earlier, which had a great hiding spot for the marauders, Severus appeared from down a different corridor and snuk behind Harry. Whom pretended not to see him. Severus grinned as he put a hand over the Heir's mouth and pushed him up against the closest wall, both their forms illuminated by the half moon which shone through a nearby window.
"Hey there, sexy." Severus purred in Harry's face, and replaced his hand with his mouth, kissing his beloved hard, one arm around Harry's waist, the other grabbing at the long hair at the nape of his neck. Harry put his hands on Severus' chest which almost made it look like he was trying to push him off.
"YOU FUCKING PERV, GET OFF OF MY SON!" James shouted, as the three marauders cast lumos at the two. Sirius was halfway morphing into a hound in anger.
Harry let go of Severus' lips and turned to them with an obviously fake shocked expression, before his face cracked. He burst out with a proper belly laugh and Severus laughed with, still embracing Harry against the wall, casually nuzzling his neck affectionately.
The three marauders looked confused and deflated, wands slightly lowered.
"Oh no, the poor young man that saved the whole wizarding world by singlehandedly ripping Voldemort's head from his torso with his teeth is being assaulted by Snivellus." Harry said in a feign damsel voice, laying one arm over Severus' shouler, leaning in and placing a kiss on his lips.
"Someone save this poor man from his fiancé." With that word, he grabbed Severus' left hand with his own, showing off the rings to the three men.
James and Remus were stunned, but to everyone's surprise, Sirius began howling in laughter.
"You know. I would be the first to punch Snivellus in the face, but that right there was a class A prank from you two." The animagus chuckled.
Harry smiled, relieved at his godfather's response.
"It does feel a bit wierd. The age gap is massive. Then again, I do see myself in Severus' shoes with this, regarding the situation with Tonks, and all that, so yes. I can give my blessing to this union, I just need it to sink in a bit." Remus said, a small smile toying at the crook of his mouth.
James looked at them, bewildered and shook his head before walking away.
Remus sighed.
"Give your father a few days, and he'll come around." The werewolf said to the clearly saddened Harry with a gentle smile.
Severus sighed and hugged Harry gently in his arms.