halacha - What constitutes the Biblical Mefateh?

I'm trying to understand the Biblical concept of "Mefateh" (a "seducer"):

1. 
   

   The Torah says (Shemot 22,15) without elaborating:

   
   

   
   

   וְכִי־יְפַתֶּה אִישׁ בְּתוּלָה אֲשֶׁר לֹא־אֹרָשָׂה וְשָׁכַב עִמָּהּ מָהֹר יִמְהָרֶנָּה לּוֹ לְאִשָּׁה׃

   
   

   If a man seduces a virgin for whom the bride-price has not been paid, and lies with her, he must make her his wife by payment of a bride-price.

   
   

   
   



2. 
   

   The Halochos (see Shu"A EH"E 177) go straight to the punishment without explaining the process,

   
   

   
   

   המפתה בתולת ישראל משלם וכו':

   
   

   One who seduces a virgin of Israel pays ...

   
   

   
   

What set of actions and conditions constitutes the Biblical Mefateh? What role the seduction part plays in it? And how it is different from regular consensual relations between unmarried grown-ups?

What must a man say and do, should there be witnesses for Pituy, what's the woman's role, what do they all claim in the court?