Hey BD 6.5,
As far as I understand it, the warmup is aimed at loosening the muscles and somewhat increasing the stretchability of the ligamentous tissues. If you go too hot you’re just going to burn yourself, don’t forget your body is just made up of chemical compounds which can react to heat. Before you hit melting points or glass transition temperatures which could lengthen the penis by adjusting the chemistry you’re going to burn your unit.
The point of warmups is making the exercises more effective, promoting blood flow for faster recovery and increased growth, and to prevent injury. Heat alone however… I don’t know any mechanisms that would cause growth by heat alone, plus the burning issue. And it would probably heat up your testicles too which is pretty bad for T and sperm production and such.
Hope that helps
February '16: 173 mm BPEL (6.81") 132 mm MEG (5.20")
November '18: 190 mm BPEL (7.48") 137 mm MEG (5.39")
Goal: A sustained 7.7" by 5.8" during intercourse