In Hentai (Japanese Anime/Manga cartoon pornography) lingo, Ahegao refers to the exaggerated facial expression many anime female characters will make in order to emphatically communicate sexual pleasure, oftentimes involving a crossing of the eyes and the tongue sticking out, with saliva or drool. Awareness of the ahegao trope has become more notable since the advent of ahegao clothing; you can find ahegao sweaters, socks, shoes, underwear, hoodies, tee shirts, pants, stickers, laptop skins, basically anything. An example.
This is a short and sweet node because there's not much content to cover, but I just figured that since it wasn't noded my conscience could not rest easy until I had noded it.
No, I don't watch Hentai.
Update: I have been informed that some of the characters on the hoodie are male, so evidently it is not a female-specific trope :p praise the Lord for gender equality.