Im a freelance photographer and have recently started learning and taking boudoir shots for my portfolio and also for amatuer models who want them for theirs.
I am always very professional about it while being easy going and fun, which gets the most natural looking shots as the model is relaxed and happy, having a fun time doing it.
Professional models have very good boundaries while being nude around you on a photoshoot while still being friendly.
However, amatuer models that are still new to doing nude shots can be a little too friendly sometimes. I try to diffuse these situations if I feel they are a bit naive and I would be taking advantage of someone vulnerable and explain to them that just because they are nude, it does not mean they are pressured to do anything sexual with me, which they appreciate.
However, sometimes there are those that know exactly what they want and will work you until they get it. I still should be professional and not give in, but sometimes I just cant help myself!