I don't think NLP is the best way to go, there is no such thing as an easy way to anchor a girl over the internet, atleast not the way you ment (Because when you meet her IRL she wont associate you anchoring with some kind of sexual thoughts, seems rather impossible).
The hardest part in using the Seduction NLP on internet is that you can just control your words your writing. Not kinetics, body language, voice tone etc, which will obviously make all kind of NLP-patterns much less usefull.
However, you might be able to use some "weassle-phrases" and try to embed commands without it being to obvious you are trying to seduce her.
You could try like "have you ever felt ......." than tell her what she should feel. The "have you ever felt" will make the phrase go through a girls "defense system", instead of commanding her "feel ..... " which is to obvious what you are trying to do and she will most likely just tell you to fuck off.
Another good one I like to use is "I heard this crazy guy talking to this random chick on the bar last week, he went up to her and started to tell her: I will go down on you, you WILL be all AROUSED and feel this INTENSE craving for sex... bla bla( you can put in whatever nasty stuff you think will turn YOUR girl on ) and end it with something like "does that really work? " . Same thing with this phrase is that you are "innocent" you are just telling her this story

(but she will get the picture of you doing this stuff to her).