Athletic ass in front of me on moving stairs

I would sign to be on the moving stairs forever if this epic girl was in front of me at all times. She looks totally athletic and her ass is from out of this world. I followed her as she ventures around the shopping mall and she went straight into the cosmetics store to buy makeup and such stuff. I wanted to tell her that she doesn't need anything because she already looks perfect, but it would be a bit awkward to approach her like that.