Put napkin into collar like this and start eating (4,2)
I believe the answer is:
tuck in
'put' is the definition.
The definition and answer can be both related to consumption as well as being verbs in their base form.
Perhaps you can see an association between them that I don't see?
'napkin into collar like this and start eating' is the wordplay.
I cannot quite see how this works, but
'into' could be 'in' and 'in' is found in the answer.
The remaining letters 'tuck' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tuck in that I've seen before include "Substantial meal" , "have hearty meal" , "Arrange comfortable retirement" , "Eat heartily" , "Go ahead and eat!" .)