Just thought I'd add my 2 cents...I certainly can't speak for other models but I'm perfectly comfortable with a photograher saying something like "I need your nipples erect for this shot," or something like that. It's VERY easy for me to know if a photog. is requesting this in a sleazy manner or requesting it because he/she really feels that it will help the shot. That said, I think if you are casual and open about it and that your intentions are not about your own desires (I don't mean photog. desires...) but about what you are trying to express in the image...you're within boundries and etiquette....
Clariss
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