Throw-back to my wild & mis-spent youth (that was a long time ago), getting girls & women to "model" for me was a pretext to getting them naked, and sometimes having sex with them. I am a (very) amateur photographer, and it is just a fun game I have done for going on 35 years.
Models off the street I always treated with kid gloves, did not push too hard, but certainly laid the opportunities out there.
Models that are known (such as a friend's wife) can be assessed by pushing more directly. Shamelessly taking your own shirt off while stating that your intention is to make them more comfortable with their shirt off is an age-old tactic. Choice of alcohol was always offered in abundance, and of course the praise it heaped on. Progression of the photographs should be slow and comfortable as possible, but if you can get a model to open her legs for the camera, letting you take full-on sn*tch pics, chances are that sex is on the table.
These days I do very little of the camera work, transitioning to showing other guys how to do it using my own wife as the model. Granted, she caught on to our wicked ways pretty quickly...
