Cockneys of London, Muscadins of Paris...

...listen to me:  if you are involved in a relationship with one of your students, you are involved in a bad relationship.  If you are involved with one of your undergraduate students, or with one of your former undergraduate students who remains an undergraduate, or with an undergraduate student who was not yours but is still an undergraduate, and you yourself are a member of the professoriate, you are involved in a relationship that is really bad news.  If you are the possessor of a Ph.D. and the person you are seeing is at your college or university and is not yet the possessor of a B.A., you need to take a serious, long look at that relationship, consider its relative inequalities and power structure (however immaterial those may seem to you), and ask yourself if it is right or fair or would seem psychologically sensible if the person involved were not you.  Because, I assure you, the answer to those questions will be no.

Ew.