Yoshino san, thanks for the post!
Yuttan is adorable.
Found a dictionary that helps with Japanese onomatopoeia words,
As Yuuri said goro goro several times...http://api.nihongoresources.com/
I entered ごろごろ into the search box in the area described as
Giongo (sound effects) and gitaigo (state descriptor) search:
And there were several definitions, including these two
Motion: roll over and over
Performing an action: to lie sprawled
Sound studio photo from nogizaka-journaldotcom
All other photos credit nataliedotmu