Some of the above have mentioned 'teasing', or we could say 'teasers'. There are many personality types and teasers is one of them. It's having control, probably knowing the male sex drive, the teasers love pushing the buttons to the limit and then pulling back for their own need to be a control freak. I have no idea what percentage of women are teasers, but most guys have dated, pursued, or been pursued by a teaser at least once in their life by the mid-twenties.
Teasers love saying the word 'no' or 'not now' but continue pushing buttons, sending off vibes to get the guy, who has stopped, to start up again. They don't mean no when they say no, but one of their no's may be the real thing. Therein lies the danger.
Guys, if you get involved with a teaser, just stop and move the fuck on to someone else. Teasers confuse the issue. Most women are just up front and no means no, stop now, don't continue. But with a teaser, it's a game. Don't play it, it can be dangerous, get the hell away, and definitely don't pursue.
Just always, 100% of the time go with the no means no and stop. The consequences of confusing a teaser with most women can be permanent. And remember, most women aren't that kind of teaser. So. NO means no.
And seriously, this is the 21st century, and in 21st century western society, women often are the sexual aggressors and they will definitely let you know without a shadow of a doubt when they want to have sex. In fact, in my life, I've mostly experienced women as the sexual pursuers. And I have always liked being pursued by women. In fact, playing a little hard to get, or naive can really bring out the fun in them.
The Linebacker
I think here, signals get easily mixed, as you dont hear tone of voice or feel the emotion in their voice, just as face to face you dont get to read their looks... Sadly, one of the things I've seen here is that a woman showing kindness... or even saying hello is taken as instant liking or invitation to be sexually forward... So what can a woman do to be more aware? Here, it's pretty hard, but aware of the words you use, words that might be used to insinuate attraction... as well as the words he uses and the amount of praise, or compliments he pays over and over... how much he wants to chat and how quickly they approach... If you get an uneasy feeling, it's probably a good sign you should ask him questions about how he feels or make sure he clearly understands how you feel about him... Hope I helped in some, small way :)