Poses as a TD, say? (4)
I believe the answer is:
sits
'poses' is the definition.
('sit' can be a synonym of 'pose')
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for sits that I've seen before include "Takes a seat for the painter" , "Is in session" , "Takes a chair" , "Takes an exam" , "Poses for portrait" .)