Contrast showers promote recovery through the vasodilation and vasoconstriction of blood vessels. It promotes bloodflow which in turn brings more nutrients to your muscles.
Using this as a recovery tool is always good because everyone has access to a shower. The best way I’ve found is to always finish with the cold and you feel great as soon as you step out of the shower, and 30 sec of hot/cold is good too.
This is one a remember reading from CT but he said that you should stick to 30s cold/ 2 min hot and depending on the workout change the temperature of the hot part. I found it just takes too long this way though, but experiment to see what works for you.