So, get yourselves into a position where you can easily rub her clitoris during sex, and use it to your advantage. Under the guise of giving her some extra special treatment, you can feel whether she’s actually close to climaxing or just faking.
Ummm I pretty much thought that was required for most orgasms in the first place.
Anyways I've never noticed that specific reaction.
The rest of the article is ok though.