.....no I don't mean get an ice cube out and get yours erect. By example I mean most experienced models are use to the terms erect nipples, etc and understand. I have heard of stories of using frozen chicken to get those puppies erect when there was no ice in the house and the model just did it that way and was so cool about it. Although I don't suggest saying, "you got any frozen chicken? I need to see nips baybee and I ain't talking cheese."
It's all about understanding the personality first. Get to know your client or subject. Talk it out way before the shoot and come to terms with terms that will be used.
Have example images around to help communicate better. Also seperate the preperation with the actual photo session by having another female in the room. Get your assistant to suggest to the model the things that need to be done. After all, the final image is what you are after, right?
J T