Step #1: Click the white space in the comment box or reply button first in order for the "Add Media" to show up.
Step #2: Click "Add Media"
Step #3: Go to the right side (where the media section pops up) and click any emoticons you want.
Step #4: Search "dancing cat" for shortcut quick list. You can also search it using the title or if you want, my username for random emoticons and they will be there. Click your choice and enjoy~
Using as icon lol