In addition to what flyingdgn said, not everyone has a same result. If you are eating a lot of junk foods, or have a body part that are in pain (no, not your private member), then the color of the mark turns out more darker in colour. When I tried it in January this year, the attendant put the suction cups all over my body, I only got bright red marks on my shoulder area. Problably because I hurt my shoulder on a football game a week before. Marks lasted about 2 weeks and they faded away. Although it really improved my shoulder tension dramatically, I could not hobbying for 2 weeks because of the marks. It was a torture not to see my favourite MPA. How the heck am I exlain the marks to her? She would probably think that I have a skin disease.