About the twin daughters, one’s ridiculously soppy (6)
I believe the answer is:
sodden
'soppy' is the definition.
('sodden' can be a synonym of 'soppy')
'about the twin daughters one's ridiculously' is the wordplay.
'about' indicates putting letters inside.
'the twin' indicates the doubling of some letters.
'daughters' becomes 'd'.
'ridiculously' indicates anagramming the letters.
'd' doubled is 'dd'.
'ones' is an anagram of 'soen'.
'dd' put inside 'soen' is 'SODDEN'.
(Other definitions for sodden that I've seen before include "Soaked to the skin" , "'Soaked, sopping (6)'" , "Made very wet" , "Completely saturated" , "heavy with moisture" .)