I believe it is the fairly standard understanding that the touching of the genitals is what takes a sensual massage into the realm of erotic massage. Breasts though may be more of a grey area that may change from therapist to therapist. Most likely, it is best to find out what the client thinks as that is what in the end is most important.
Inspired Touch Massage Therapy for women by appointment only. Located in the West Palm Beach FL.
To my mind all massage can be sensual to a greater or lesser extent. I believe that for a massage to be a truly sensual experience--both giver & receiver must be naked. I'm a naturist so I've absolutely no inhibitions about my or anybody else's body. The room must be really warm otherwise the receiver will not be comfortable. You must include the buttocks & I like to do light figure of eights around & between the breasts as well as very light brushes of the nipples. I think it's sensual to work on the tops of the inner thigh & to come down as far as the pubic bone on the abdomen. However once you move onto yoni/lingham massage you've definately crossed into erotic.
I like juliemil2003's "Be Free be nude be natural"
There is a movement under foot to bring massage into the mainstream of health care. As such, breast massage should be part of a regular program available to clients that are interested. There is a huge difference between wellness breast massage and sensual breast massage and even fondling.