Well, if a guy has a very small trouser snake and the woman he is banging fakes an orgasm maybe she isnt really getting anything from the sex. I mean she probably loves the small edowed guy she is with and doesnt want to hurt his feelings because he cant get her off so she fakes an orgasm. Or he can really suck in bed. This could be one of the reasons why some ladies fake it.
Now Im not saying that all woman fake orgasms, lol. But that could be one of the reasons.