Reasons why stacked nurse fantasies are so popular:
1) Excluding hookers and massage-parlor girls, nurses are the only women you don't know on a personal basis who can (legally) wash your penis and balls, one of the great pleasures of being a man.
2) Nurses are nurturing and don't like to see men suffer with blue balls or bloated shafts.
3) By the nature of their jobs and training, nurses are health-oriented, sanitary, caring and cock-worshipping. This is the kind of woman you want manipulating your Johnson whenever possible.
4) Their uniforms are exciting, although in real life, nurses don't wear open-toed six inch platform shoes, corsets, split-crotch panties and strapless push-up bras one size too small.
5) Nurses know every inch of the male anatomy and how it works.
6) Nurses are discreet and confidential.
7) How often do you get to fuck in an electrically operated bed?