If I'm going for a big ball pump then I'll take it slowly with low pressure for hours. I always pump wet and I think that helps a lot. I'll make sure the water is on the hotter side of warm and will change it if I feel it's getting cool, so for me, without a heat pad, insulation of the tube is the key. Before I change the water I will go through a cycle of increasing the pressure to as high as i can stand and keep it there for 30 seconds, then let all the pressure go, then ramp it all the way up again. I'll do that for about 5 minutes then get new warm water in after a bit of a massage.