This is of course after you've built some level of attraction. It shows that you are non-needy and a challenge. Girls don't want guys that are easy because they see these men as low value. So, if you did a pretty good job with the attraction part, the only thing you can do is fuck it up by seeming desperate. Everyone wants what they can't have. So put the phones down and stop trying to think of that magic text that's going to make her panties drop.