You were accompanying Arthur on a robbery of a steamboat full of rich gamblers and such. The both of you disguised to be rich oil producers near the area. Some apparel on your outfit having brought out some areas of your body out more than others.

Arthur was walking beside you. Glancing down at your chest and staring. A slight hint of blush on his face. Eventually you caught him in the trance and he quickly snapped out of it. Looking at your face and trying to act as if he was innocent.