Massage therapists are professionals who don't take your body form into consideration when they are giving a massage. In a sense, they are like doctors because massage therapists do not look at their clients' bodies judgmentally.
Experienced massage therapists have also seen all kinds of body shapes and sizes, so nothing is new to them. They are not judgmental about your body or anybody else's body. They are taught to look at a massage as a gift that everybody should be able to enjoy without being concerned about what they might look like without their clothes.