Your partner opens one club in 2nd seat. Right-hand opponent overcalls one diamond. You respond one heart with a nice 10 points:
You
Left-hand opponent passes, partner rebids two clubs, and right-hand opponent rebids two diamonds. That’s where the bidding ends.
You lead the ace of clubs and see this dummy:
Dummy
Partner encourages with the eight of clubs, so you continue with the nine of clubs to partner’s king. Now partner continues with the deuce of clubs, queen of clubs from declarer, and you ruff with the five of diamonds. What do you do next?
Larry Cohen provides some guidance on his site: https://www.larryco.com/bridge-articles/defensive-signals-signaling