"Am I cute? uguu~"
This expression came from the H-game (PC)/PS2/DC/anime Kanon. Tsukimiya Ayu line (and probably the most famous throughout Kanon). This is her expression when she moans, or whines (like eeeehh, but more original). It would later become associated in the West with an infamous quality image of Hanazono Karin from Kamichama Karin.