People in Japan are grabbing and squeezing animals' cheeks in a trend called もちもち, or "mochi mochi."
The phrase is usually applied to the chubby, stretchy cheeks of young children.
But recently, people have begun to notice that animals — specifically shiba inus — have notable stretchy cheeks.
モチモチ猫もいいけど モチモチ犬はいいよね|ω•。 ))
もちもち
"Mochi" in Japan is a glutinous rice cake that can be eaten as a sweet treat or with soup like a dumpling.

Obivously Japanese pet owners have noticed a similarity between their pets' cheeks and the popular food.
もちもち
Caution: Attempts to "mochi mochi" pets may always not go as planned.
コーギーももちもちしたかった
Twitterで流れてきた柴犬もちもちするヤツ真似しようとしたら激おこなんだけど……