Drunk!Harry and Drunk!Greg
It was well known in Harry's close circle of friends that he got rather affectionate when drunk. He liked to be close to people, something that he'd never admit without the benefit of alcohol. It was also something he was rather unaware of himself, as his mind was always cloudy after three or four drinks. Tonight was no exception, except he'd had nearly double the number of drinks and his already lowered inhibitions were rock bottom.
Which, Harry mused to himself, was why he found it impossible to move away from Goyle. He was just so tall and warm, and big enough that Harry could rest against him without worrying about dropping to the floor. Unless he drops you, an inner voice said, but it was far away and muffled. If that happened, Harry could always arrest him for assaulting an Auror. Yes, that was a solid plan.
"Course I read your list. Had to decip...decid...figure out if you were asking for anything illegal. Socks aren't illegal, but it should be to ask fro them for your birthday. The Dursleys used to give me Dudley's old socks for Christmas you know. It was disgusting." He tilted his head up, and smiled blearily at Goyle. "I bought you new socks though. Nice ones. To throw you off the scent of my suspicions."
He patted Goyle's chest. "But you're actually pretty boring. Did you know that? I'm sad there hasn't even been anyone for me to threaten tonight. I like threatening people who need to be threatened."