Given his muggle dad and the working class district he grew up in I've always thought that Severus would have had other, more feral friends, than just Lily in Cokeworth. There wouldn't have been much entertainment indoors, so it is likely that he would have spent most of his time playing out of doors with other kids from the surrounding streets when not in school. There wouldn't have been any adult supervision. I don't think that JKR acknowledges how au-fait he would have been with sixties and seventies English muggle culture.
The story takes place in Cokeworth at the end of the Hogwarts summer holidays in 1990. Rated M for language and adult themes.
Severus completed a second set on the chest press. Merlin, this place stank of sweat. Sweat and liniment. The walls were permeated with the stuff. The gym had seen better days but it suited Severus' purposes. He'd started coming here a few years ago during the summer holidays while he was resident at Spinners End. Keeping fit for the traumas to come if Dumbledore was right about the Dark Lord returning. But really he'd been bored and wanted something to pass the time. He must have walked past the entrance a hundred times without giving it a thought. Then one grey, damp Northern summer's day, at a loose end, he stepped inside.
And here he was in a faded black tee-shirt and sweat pants pumping iron. Severus chuckled to himself at the image that conjured inside his head. Pumping iron, ha! Whatever would Minerva and his other colleagues think if they could see him working out in a muggle gym. Never mind Lucius and his Death Eater acquaintances. Mind you, Poppy would probably approve. Severus smirked at that thought.
Billy who ran the gym gave him a nod as he wandered past. He was a broken-nosed ex-pug. One of those guys with no neck. Reminded him of Goyle senior. He ran a boxing club for the local youths and the gym included a ring. He had tried to get Severus to spar a few times but so far he'd always refused. Maybe he'd give it a go some time.
The club was meant to keep the local kids out of trouble and it received financial support from the local council for this endeavour. Kids like some of those Severus used to know. Severus had by no means been the only deprived, neglected child in Cokeworth, or indeed Spinners End. There were a few of them that Severus had gravitated towards in muggle primary school before he went to Hogwarts. He'd also kept up with them in the holidays away from Hogwarts, when he was not with Lily, until he finished there and his decisions took him away from Cokeworth for a few years.
Davy had been the lad he was closest to. A scrawny little skinhead with shiny red DMs when he first met him. He'd been so proud of those DMs. Davy who'd introduced him at a tender age to fags and wank mags. Lily thought he was a "wrong un". Mind you she thought all the other lads he got on with were "wrong uns" as well. No change there then. There again she was probably right. Davy returned the disdain in kind thinking Lily was a "stuck up cow". He was probably right too.
As they got older booze and pills followed the fags and mags as Davy's choice of entertainment. The pills never worked for Severus. Something to do with wizard bio-chemistry. Davy also introduced him to muggle music, first glam in his early years at Hogwarts, and then more notably, the punk and new wave bands that flowered in the years after he lost Lily. You could just make out the words Joy Division on his black tee-shirt, a gift from Davy years ago. Poor Davy, long gone. Choked on his own vomit when he miscalculated his intake of pills and a half bottle of White Horse.
The others were mostly gone as well. Some had been in and out of prison. One stabbed to death over a dispute in a chip shop. Stabbed in a chip shop. You couldn't make it up. Merlin, Cokeworth was a fuckin khazi. To think he had spent so many afternoons talking to Lily about how they were both going to get out of Cokeworth. She had he supposed. But not in the way they'd wanted. Not then. And he was still here.
He had Hogwarts he thought morosely. That promised world of magic and wonder that he and Lily so much looked forward to as children. But in the end it turned out to be just a khazi of another kind. Suddenly unsettled by his gloomy turn of thoughts Severus decided to finish his session. He needed a ciggie. He turned off the old Walkman he had listened to in the gym and pocketed it. Another gift from Davy that was no doubt stolen. Glad to get outside he headed towards the park where he'd first met Lily. If there were no kids about he'd go and sit on the swings and smoke.
Think about what really was nagging at the edge of his calm. The Potter spawn who was going to arrive at Hogwarts in a years time. Lily's boy. Jesus, some higher being, whether muggle or magical, wasn't happy unless he was pissing on Severus Snape. He sighed and lit up taking a deep inhalation and releasing the smoke through his nose. He flicked the Walkman on, his eyes un-focusing as he stared out across the park. "Every day's like Sunday. Every day's silent and grey".