The thing is that Ichigo knows he's exaggerating. Shinji was just teasing him, as Shinji does. It's Shinji's thing. It wasn't mean spirited so Ichigo is all set to get his temper under control via a couple of hours of sulking. He'll move on after that.
Furthermore, Shinji already apologized for the whole meeting thing, three days in. And Ichigo accepted said apology. Normally, that would be the end of it. It usually is, Ichigo already "won", after all. Yes, Ichigo is still feeling a little vengeful but if he allows it, it will pass soon enough, no one being the wiser.
That's not what ends up happening.
Call it payback for the bar, if you must.
What ends up happening is that a small lightbulb lights up over Ichigo's head as he walks by some important dude's office. Well, Ichigo thinks to himself, if Shinji can have some fun with Ichigo's dilemma, why can't Ichigo have some fun with Shinji as well?
Decision made, he goes looking for another blonde. He's Kisuke's favourite student (never mind that he's also the scientist's only student) and that comes with some perks. It takes about a week to get everything ready. It's just as well, that way Shinji might get lulled into a false sense of security. Let him think he won. The sadistically gleeful grins on Kisuke's and Hiyori's faces as Ichigo explains his plan are a little unsettling but also a great reassurance that he has their full support.
That's how he ends up in Shinji's office, Hiyori working as a distraction as Rukia, Renji and him put the little gadgets on the underside of everything Shinji owns.
"This," Rukia says with relish, "is going to be awesome."
Ichigo just sends her a smug grin from where he's kneeling by Shinji's desk.
Rukia returns it with a devious smile. "The two of us," she tells him while she points between the two of them, "we work great together."
"Hey!" Renji snaps from beside the door. "What am I? Chopped liver?"
Rukia doesn't miss a beat. "Useful but unappealing? Yes."
Renji splutters.
It takes Shinji about two days to realize that everything he owns in his office is slowly moving to the right. About a day more passes before he finally realizes that there's no one infiltrating his office to do it, a couple more hours and making a mess of his own office before he finds the little gadgets and a lot of begging for Kisuke to concede to turn them off.
They have it all on HD, courtesy of Kisuke's cameras. Watching Shinji slowly becoming increasingly twitchy is wonderfully therapeutic.
Of course, Ichigo is fully aware that Shinji is going to retaliate. So he's not surprised when he finds all his whites have all been dyed pink while he was away. Knowing doesn't make it any less irritating when he finally notices that it's the exact shade of pink Kyoraku wears over his captain's haori.
Well then, if pink is what Shinji wants, pink he will get. Ichigo goes to Rose. It takes surprisingly little convincing to make off with the other vizard's hair dye. His new plan is made easier by Shinji's obsession with his own hair, the man has so many hair products that his bathroom looks like a saloon. Ichigo simply replaces one of the treatments with Rose's hair dye.
If Ichigo also takes the opportunity to sprinkle some obnoxious yellow glitter over the other man's clean clothes, well that's nobody's business but his own. Besides, watching Shinji looking sour, pink and glittery around Seireitei is enough to make him feel smugly satisfied.
Shinji's revenge comes after his sparr with Kyoraku. Ichigo comes back to his room to find everything he owns somehow glued to the ceiling. He allows himself a minute to wonder how even his mattress and pillows are perfectly positioned before he plans out his next step.
Ichigo hard-boils all of Shinji's eggs and then returns them to their spot. Say goodbye to your morning omelettes, asshole. And because Ichigo has some left-over frustration to work on, he also changes all the sugar for salt and vice-versa and makes sure that all of Shinji's coffee is now decaf. Even the one on the fifth's compound.
His first inkling that he might have gone too far is when that retaliation takes a little too long in coming. At first, Ichigo thinks that Shinji is simply planning something big and so the teenager gets so very twitchy. But time goes on and nothing happens. After a while, Ichigo is so done with the suspense that he goes to look for the blonde on his office.
He finds Shinji sprawled on the floor, surrounded by empty coffee pots and messy paperwork. The entire fifth division is encased in chaos and panic. A part of Ichigo is sorry for him, the rest of him is so done with the drama that he kicks the older man on the side. Shinji only moans pitifully and moves with the kick.
Ichigo feels his scowl deepen. "At least fight back!"
"It'd be too much work."
The poor idiot sounds so bone-deep tired that Ichigo feels a little sorry. Just a tiny bit, though. If Shinji wasn't so much of an ass, Ichigo wouldn't have pranked him the first time. And the sight of his still pink hair is just too great. Ichigo is going to keep the pictures forever.
Still… Really? All of this for coffee?
"If you let this one go," Ichigo offers, "I'll help you with the paperwork."
Shinji narrows his eyes at him and then shots a look at his coffee in slow realization. With energy Ichigo didn't know the older man still had in him, Shinji throws himself to the nearest half-filled pot and drinks it as if to prove a theory. Maybe he can? Ichigo doesn't know, he's always been more partial to tea.
The look of betrayal Shinji is sending the leftover coffee is hilarious, though, and it takes a lot of willpower for Ichigo to swallow the evil laugh that wants to bubble out of his mouth.
"Fine. But throw in a coffee pot. No decaf."
There's something like desperation and hope in Shinji's voice and Ichigo thinks that maybe messing with the blonde's coffee should be considered drastic measures from now on.
They still shake on it.