Found it on this awesome post: https://e621.net/post/show/729722

Does it meant to me "Xs for eyes"?

Dunno about x, but if you add the underscore to x x in the tag list (to fill in for the space), you get x_x, which looks a lot more like a face.

should be aliased to x_eyes, while x needs cleaning out. Sometimes, it's X_eyes, sometimes it's an X_mark, sometimes it's just a letter.

Furrin_Gok said:
x_x should be aliased to x_eyes, while x needs cleaning out. Sometimes, it's X_eyes, sometimes it's an X_mark, sometimes it's just a letter.

^_^
o_o
>_<
;_;
x_x
Funny thing is that those tags are actually pretty useful to get images with exact motion as ^_^ means character having that kind of face, instead of just being happy.

Mario69 said:
^_^
o_o
>_<
;_;
x_x
Funny thing is that those tags are actually pretty useful to get images with exact motion as ^_^ means character having that kind of face, instead of just being happy.

^_eyes
shock_eyes
This one's hard to get without mixing it up with <_>. Wincing_Sideways_v_eyes? Inward?
semicolon_eyes
x_eyes

Mario69 said:
^_^
o_o
>_<
;_;
x_x
Funny thing is that those tags are actually pretty useful to get images with exact motion as ^_^ means character having that kind of face, instead of just being happy.

Furrin_Gok said:
^_eyes
shock_eyes
This one's hard to get without mixing it up with <_>. Wincing_Sideways_v_eyes? Inward?
semicolon_eyes
x_eyes

I agreeing with Mario here, because :3, :D, :P, is used.
You're saying we should change them to <word>_<SmileyFace>