Relax and tell porky feathers (3,4)
I believe the answer is:
lie down
'relax' is the definition.
(I've seen this before)
'tell porky feathers' is the wordplay.
I cannot really understand how this works, but
'porky' could be 'lie' (I've seen this in other clues) and 'lie' is present in the answer.
'feathers' could be 'down' (down can mean bird feathers) and 'down' is present in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'and' acts as a link.
Can you help me to learn more?
(Other definitions for lie down that I've seen before include "Assume recumbent position" , "Become 14" , "Take a rest (at length!)" , "Take to one's bed" , "Short rest on bed/sofa" .)