Don’t get so excited and don’t go topless! (4,4,5,2)
I believe the answer is:
keep your shirt on
If this is the answer I cannot explain how the clue works.
Can you help me to learn more?
(Other definitions for keep your shirt on that I've seen before include "Unlike a ruined gambler" , "Not topless please" , "Avoid exposing body to sun's rays" , "Chill out!" , "remain cool" .)