I definitely note nothing ahead of sex turning up occupying amounts of email (2-5)
I believe the answer is:
in-boxes
'turning up occupying amounts of email' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.
'i definitely note nothing ahead of sex' is the wordplay.
'definitely' becomes 'n' (I can't explain this - if you can you should believe this answer much more).
'note' becomes 'b' (musical note).
'nothing' becomes 'o' (looks like zero - 0).
'ahead' says to put letters next to each other (some letters go in front of others).
'of' is an anagram indicator (the answer comes from or 'of' the letters).
'sex' anagrammed gives 'xes'.
'i'+'n'+'b'+'o'+'xes'='IN-BOXES'
Can you help me to learn more?