approach invitation

Not a field report, just the weird story of a funny approach I made that made me think I was tripping or daydreaming. Just wanted to share. University campus. Dead hour. Deserted everywhere but the classrooms. I head to the student center/food court and the few people there are eating or on...

What are signs a girl does not want to be approached? What are signs that the girl is nervous and not receptive? What are signs that the girl is polite and does not want to be approached? If you have an example you want to provide, please provide accurate facial and body language descriptions ...