Good twintails day!
A Japanese pun that involves numerical wordplay (also called Goroawase). 11 can be pronounced as "ii", which is Japanese for good and also why you see a lot of these "good XXX day" things during November. As for why 22 is the date for twintails, it has to do with the original twintail day, which is 2/2. 2/2 is chosen as twintail day because 2-2 looks like the two tails of a twintail.Pan paka pan!
Arisu has evolved into Twintail Arisu!
Pan paka pan is the onomatopoeia for fanfareYuzu's also matching with me!