Some things to think about:
Consider Sam really liking to wear Peter’s nerdy sweater that probably has like bunsen burners and test tubes knitted onto it. It was already too big for Pete, so he’s basically swimming in it because he’s so tiny. And of course Sam keeps complaining about how horrible and dorky it is, and how huge it is on him, though he does take advantage of the sleeves being too long to smack Peter in the face with the hanging bits.
Whenever someones gets frustrated at his complaining and asks why the heck he’s wearing it if he hates it so much he says its because it’s warmer than anything he owns (and complains about the freezing NY weather for hours whenever its brought up) but what he’ll never admit is that he also loves it because its so very soft and smells like Peter and makes him feel like his bf is hugging him all day long.
Consider how much Sam likes to sit in Peter’s lap. How it’s his favourite seat in the whole world and he crawls up there literally every chance he gets no matter where they are or what they are doing. Their friends don’t even bat an eye anymore, just accept it as the way things are, though of course the first few times they teased them mercilessly. But even the teasing wasn’t enough to make either one of them stop.
He sits there when they are fighting, when they want to snuggle and when they are studying. At school and at home and SHIELD and even at restaurants once the meal is over. Sometimes Sam sits in his lap and plays his DS and Pete just puts his head on his shoulder to watch and kisses his hairline every once in a while and cringes whenever Sam shouts abuse at the screen when he’s doing badly because wow Bucket-Head you’re so loud, seriously your mouth is right by my ear dude stop.
On a related note please also consider Pete reading, or doing some homework when Sam slips up under his arms onto his lap and tries to see how long it will take for Peter to get distracted as he kisses his neck. Imagine how hard Pete would try to ignore him and keep reading because no, he refuses to give in this time, even when Sam’s mouth feels so good and is peppering little marks onto his skin. But then Sam sucks on that one spot that makes him melt and grazes his teeth along his jaw, and Peter just kind of tosses his book onto the floor and grabs Sam’s face to kiss him, and pretends he can’t feel the triumphant smirk against his lips.
And finally consider if you will Peter volunteering to ‘help’ Sam make cookies every time he does it, but it’s pretty obvious that he only does it so that he can insist on licking the bowl/eating the dough. And every single time they cook 'together’ he ends up burning his mouth stealing a cookie (or any type of food really) right after it comes out of the oven, and Sam laughs at him for a full minute before he offers to kiss it better. Consider how much better cookie flavoured kisses would be, and how Sam would definitely like it best when Peter tasted as sweet as he kissed.
Thank you for your consideration and have a good night.