Shellfish on edge (7)
I believe the answer is:
This clue could be a double definition.
'shellfish' is the first definition.
(I know that scallop is a type of shellfish)
'edge' is the second definition.
The answer and definition can be both to do with contact as well as being verbs in their base form.
Perhaps there's an association between them I don't understand?
'on' is the link.
Can you help me to learn more?
(Other definitions for scallop that I've seen before include "Shellfish that's also plc" , "Seafood - shell" , "Mollusc or lacy edge" , "Marine mollusc" , "one may be in one's shell" .)