Boobs.
Guys are fascinated by them.
Through single-digit ages, they find the very concept of them hilarious, and when puberty kicks in the mere thought of lady-lumps generally causes some movement in the trouser department. These weak-willed creatures will follow them anywhere and they will do almost anything if it means simply being permitted to gaze upon them for a few moments more.
The entertainment industries, from the big movie makers to the lowly art whores (like me) know this, and have played upon it for years in order to separate males from their money. As a result, mass media is awash with the female form in all manner of provocat