The second time:
By the time Potter completed his Fourth Year, faced the maze, won the tournament, and resurrected the Dark Lord, Severus knew that the last thing on his mind should be the unintentional lyrical reference. He was under immense pressure. Spying in the first war had been harrowing, but adding Potter and the Ministry into the mix was wreaking havoc on his nerves. Even still, there were late nights where the boy's developing voice shouting that single line would leap into his thoughts unbidden and he would find himself snickering into a tumbler. It was ridiculous, but one must get their entertainment from somewhere, and there wasn't a lot else in his life right now that was worth snickering about.
At least he'd been able to hide this small entertainment from Potter. It had been hard, the first time he'd locked eyes with that indignant emerald gaze after overhearing the conversation. The First Task, and Potter's heart-stopping survival of it, had proved to be more than enough to finally escape the overwhelming urge to laugh at the young man's expense. Loathe as he was to admit it, Potter was damned lucky to have inherited and significantly bettered his father's natural skill on a broom. Most handlers weren't stupid enough to try and outfly a dragon, but Potter didn't tend to use logic when confronted with overwhelming odds. In the unlikely event Severus survived this hellacious year, never mind the war, he looked forward to the day when people protested the autobiography of the Boy Who Lived as being unrealistic and impossible.
Today, however, he could imagine not even that niggling memory and jaunty punk tune playing in his head could relieve the migraine and aggravation of having Umbridge in his classroom a second time. Did the woman think she was being subtle by intentionally choosing the lessons Potter was in? It was obvious, to everyone but the brat himself apparently, that she was doing it to goad a further reaction from the imbecile.
Albus' warning this morning that it may be necessary for him to teach the Gryffindor Occlumency only made matters worse. It made so much less sense for him to teach him, as opposed to the Headmaster, and Albus couldn't even give a satisfactory explanation for why they were necessary. Not that arguing with Albus Dumbledore ever got anyone anywhere, hence the migraine.
Trailing down the corridor, coincidentally just ahead of the awful pink toad (an apt descriptor from the students that Severus dearly wished he could use aloud himself most days), he approached his waiting Fifth Year class. They all spotted Umbridge behind him and he heard Potter groan loudly, drawing Granger from the homework she was reviewing.
"What now, Harry?"
"The bitch is back."
It took a monumental amount of fortitude for Severus' steps not to falter as he reached his classroom door, luckily able to turn away from his audience as he tried to school his features. Had Petunia kept Lily's records? She'd hated them when they were kids, but Merlin, it was like the boy was purposely testing his control. Stifling a snort, he moved swiftly to the board, forcing himself to maintain a composure he knew was dangerously close to slipping. Lily's obsession with the flamboyant artist had been hard enough not to laugh at when they were 13. At 35, the memory should haunt him. Instead, his frayed nerves wanted nothing more than to collapse into that wheezing, chuckling teen again. The boy was going to be the death of him.