together? 

It's late June, final year of junior high, when the idea first arises.

It's late June, years and years later, when Matsuraiken is finally forcibly closed and the idea arises once more.

Two instances, then years apart, when Yoshida's idea of opening a shop with Muramatsu and joining their businesses comes up.

brontide

A solid hit to his shoulder steals his attention. Terasaka tenses and rolls over, lips parting only to seal themselves once more at the trembling shadow next to his bed.

Itona.

Itona has a nightmare during a sleepover and goes to Terasaka for comfort. 

wax crayons

Korosensei whisks into the classroom, eyes flinging to the still-glowing device in the corner. “Terasaka-kun, you called–?”

His voice cracks in his throat as his gaze hooks onto the wriggling bundle of clothes. Four wide-eyed faces full with baby-fat stare up at him.

“So,” Terasaka says with a strained grin as a four-year-old Itona pokes Korosensei’s tentacles, “I can explain.”

Terasaka would like to make it completely clear that he was against the time machine from the start. He would also like to make it completely clear that any situation wherein he’s been assigned the voice of reason is one guaranteed to go to shit.

So, for once, none of this is his fault. His friends have been turned into versions of themselves from ten years ago and he just wants them back, but now he's stuck babysitting them.