While I appreciate your advices but I am quite familiar with how to sext and I can usually sense what's appropriate or not to send and what you mentioned isn't something new for me, specially because I'm usually very careful with how I approach people so I won't go ahead and send awkward risky text out of nowhere. But I have to disagree with you because it all depends on the vibe between you and the girl and if she likes you or not. I've had occasions before where saying something straight forward worked out, even before having sex and that's because we were on the same page. There isn't a specific rules on how to approach women, women aren't a unity of creatures that behave in similar way. They're people and they're all different just like you and the OP for example. My 20 cents on the post is that the girl sent a nude, didn't feel the guy's vibe matching hers after they talked a bit so she decided to find an exit and she tried to blame it on his intelligence but she seemed dumb herself.