Bruce had noticed that sometimes Damian acted a little differently than usual, so of course, instead of talking to the boy, he did research on his own, after about two hours he came to the conclusion of age regression.
Though the problem was, if he was wrong, Damian was sure to give him an earful about not being childish. So he had to experiment, had to ease his way into it, it started with popsicles, and then he started replacing those in the freezer with teethers, it was a test, but Damian didn't need to know that, it was the boy's choice if he would actually use them or let them thaw, but he used them, Bruce was right, he knew he was.
Along the way the rest of the Batfamily seemed to notice as well, adjusting surprisingly easy, so here they were, in the living room, the now shy little Damian held in Bruce's lap, as Steph sat beside them on the couch, gushing over how cute Damian is, Dick sat on the floor by Bruce's feet, they had all grown rather protective of Damian while he was regressed, but Dick's level took the cake, Jason and Tim sat not far off to the side, Cass and Duke were also sat on the floor, though next to Dick, everyone seemed to be watching the regressed Damian, even Alfred who glanced over every now and again from the kitchen.
Steph: "Aw, aren't you the cutest widdle baby ever, yes you are"
She baby talked, Dick looked amused, Jason scoffed and rolled his eyes.
Jason: "Leave the poor kid alone you're gonna confuse him."
Jason teased.