Headcanon: bc Bruce chews him out everytime he curses in front of the new batkids, Jason has started to use “mcfreaking” and “fuckening” instead of fucking, as they’re technically not curse words and hey! It annoys the hell out of everyone.
(Except for the actual new batkids. Stephanie and Harper start shamelessly using them as well, which doesnt surprise Bruce on the slightest. However, the day Duke lets out a “you fuckening did it, batman”, and Cass nods solemly and replies “he mcfreaking did that” he decides nothing is sacred anymore)