Sheriff Stilinski got out of his car on Saturday night at about 2 in the morning after working a night shift, when he was met with a very familiar site. He had noticed the many cars when he first pulled in, so he knew the pack was in there with Stiles.
Since he was a sheriff, and a nosy parent, he went through the back door so the kids wouldn't know he was there. He came in without being noticed and silently slinked into the kitchen. He couldn't hear any laughing from the Living room, so he went out to see what they were doing.
After getting himself a glass of water, he walked into the living room to access the situation. All the lights were off, there was chocolate, thai food, popcorn, soda and teenagers strewn across the floor.
The tv was on and it looked like they had been watching Nemo. Allison and Scott were practically laying on each other in the corner of the living room, Boyd and Erica were cuddled against the futon, Jackson, Lydia and Danny on the rug and all were fast asleep. Sheriff stood for a minute observing them and taking a moment to enjoy the silence in the house. That was before he heard a whisper and a giggle coming from upstairs.
He scans across the pile of sleeping teenagers and tries to see which ones are missing. Isaac is missing he concludes, and so is Stiles- why hadn't he noticed that first? Sheriff takes his shoes off at the front door and slowly and quietly walks up the stairs. When he gets up into the hallway he notices light coming from Stiles' room. The door is slightly angled open, enough where he can see them but they can't see him.
He peeks in through the door and sees something that makes his heart melt. All the pillows and blankets on Stiles' bed are formed into a big den like thing, with Stiles and Isaac in the middle. They're watching a video on Stiles' laptop while being cuddled together. Guessing from all the giggling, the video isn't a very appropriate one.
He's about to pull the door open and tell them to go to sleep when Isaac puts an arm around Stiles and gently kisses him on the cheek. Stiles doesn't even react just tilts his head so Isaac can get his lips.
They resume watching the video until Stiles says he's tired and turns off the computer. He gets out of bed and tucks Isaac in before opening the door and going to the bathroom. When he comes out he passes Sheriff and his spot behind the door and whispers quietly " Night dad" as he passes by.
Sheriff wonders how Stiles knew he was there but doesn't leave his spot from behind the door. He watches as Stiles gets into bed and wraps his strong arms around Isaac.
He watches as Isaac turns and nuzzles into Stiles. He watches as they share a kiss before finally falling asleep in each other's arms. He quickly pulls out his phone and snaps a picture of the two before leaving his spot from the door and going to bed. His last thought that night was " That picture in definitely going in the Christmas card."