Usually used in reference to an unattainable male celebrity, this is a title given to the one person who's every word, action, or look most quickly makes the speaker's vagina
wet for their
cock (or fingers/tongue/whatever). It is implied that the speaker is (or would like to be) a
sub with this person as their
Dom in a
D/s relationship; as the Pope is the leader of the Catholic church, the speaker would like for this person to be the leader of their vagina.