From Urban Dictionary:
This expression came from the H-game (PC)/PS2/DC/anime Kanon. Ayu Tsukimiya’s line (and probably the most famous throughout Kanon). This is her expression when she moans, or whines (like eeeehh, but more original).
Ayu: I’m cooking cookies.
Yuuichi: I bet they’ll taste terrible.
Ayu: Uguu! I’ve learned how to bake from Akiko-san!
Yuuichi: You can’t learn how to bake with just watching in a day..
..although I’ll eat them if you manage to make them look good.
Ayu: Really?! Then I’ll do my best!
Entirely too much “uguu” here
‘The Kult of Kontrived Kawaii’ has little to do with genuine, spontaneous kawaii and is my parody. Things that were originally kawaii that have lost original meaning to me. This is of course, entirely subjective but usually good for a laugh.