It's a realy wierd japanese/chinese/korean involving mostly with anime or manga of an orgasm facial expression. A VERY STUPID ORGASM FACE. They basically have their eyes roll back, tongue out and a very stupid face when they orgasm. It's almost like an eye roll orgasm but with more dummy face involved.
It also similar to an eye roll orgasm, since AHEGAO involves eye rolling orgasm and latley camsluts from FreeBestCams.net, chaturbate and MFC have been putting vibrating panties and make people tip and they start shaking like a demon possession, doing eye roll orgasms and ahegao type orgasms for more money and yes, it's a turn on.
Guy: Just saw this camslut rolling her eyes and getting possed by a demon on a camsite.
Guy 2: Sounds like an ahegao! She had that stupid facial orgasm?
Guy: Yep, pretty stupid.
A combination of the Chinese word "ahe"(meaning luck or wellnes) and the word "gao"(meaning very or a lot).
Ahegao thus means a lot of luck or very lucky.