Teasing will happen if she is comfortable with you. Subtly ensure her that you're not LE. Though teasing will happen more likely than not. My first massage, she's the one that kept brushing my crack, and I didn't anything to get her to that point.

I generally start off with a big hug and move her hand to my cock and whisper I like a lot of touching there. Seems to work pretty much all the time. They certainly get the message I am not LE.