“I use the hottest water from my tap onto my washcloth, ring it out a little, then put on my face/neck, but the warmth dissipates quickly and barely lasts for 30 seconds. So I repeat 2 more times. How do you get yours to last 3 minutes?”
From a performance standpoint it is OK for the warmth to dissipate. If you prefer a more luxurious experience then yes, repeat warming the washcloth. Hope that helps!