Smiles smugly as text describes distress (6)
I believe the answer is:
smirks
'smiles smugly' is the definition.
(I've seen this in another clue)
'text describes distress' is the wordplay.
'text' becomes 'SMS' (abbreviation for Short Message Service).
'describes' is an insertion indicator (describe can mean to form the outline of).
'distress' becomes 'irk' (to irk is to annoy or distress).
'sms' going around 'irk' is 'SMIRKS'.
'as' is the link.
(Other definitions for smirks that I've seen before include "Conceited smiles" , "grins" , "Smiles foolishly" , "Smiles smugly" .)