Closing wound relies thus when laughing! (2,8)
I believe the answer is:
in stitches
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for in stitches that I've seen before include "Laughing uncontrollably" , "extremely amused" , "much affected by comedy?" , "Laughing a lot" , "you may be laughing" .)