Presses the incest, crumpled one to pack in (7)
I believe the answer is:
incites
'presses' is the definition.
The answer and definition can be both to do with communicating as well as being verbs in their -s form.
Perhaps you can see a link between them that I can't see?
'incest crumpled one to pack in' is the wordplay.
I cannot really see how this works, but
an anagram of 'incest' is 'ncites' which is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
'the' acts as a link.
Can you help me to learn more?
(Other definitions for incites that I've seen before include "Provokes to action" , "Eggs on" , "Provokes or stirs up" , "Encourages" .)