Well with heat soft tissues, ligaments, and collagen do become more elastic and easier to expand. Heat expands almost everything. Your penis Is comprised mostly of this tissue, and cold will cause the vasoconstriction on the soft tissues making it smaller. So it absolutely makes sense that your penis will appear bigger coming from a warm pump instead of cold.
This smaller apprearence easly turns people off to the idea of it not working or as effective for girth and I will elaborate on this so bare through this. Again my initial posting is not against the use of Heat or heat over ice or cold as they both work targeting different functions.
With length work heated soft tissue mentioned earlier are easier to expandand and stretch. When your penis cools it starts to contract and go back to original state. This is why in the
SRT theory they mention in healing in the expanded state When you put your heated / stretched penis In cold water and pump cycle, the pump will hold or surpass the expanded state. The the cold forces the tissues to cool and contract in the expanded state. Helping to cement gains.
With girth and where it's important works differently. As mentioned the cold causes vasoconstriction or shrinkage to soft tissues. BUT it causes increased vasodilation smooth muscle relaxation . For girth gains and penis function smooth muscle is everything. This extreme relaxation and vasodilation makes it eaiser for the CC to relax and stretch intnernaly, but the cold is making it constrict on the outside making it looks smaller while alot is actually happening internally
Now remember how I mentioned heat stretches? This is going to sound crazy but the cold will eventually increase the internal heat inside your penis. This is due to what is called the " hunting reacction"
"Vasoconstriction occurs first to reduce heat loss, but also results in strong cooling of the extremities. Approximately five to ten minutes after the start of cold exposure, the blood vessels in the extremities will suddenly vasodilate. This is probably caused by a sudden decrease in the release of neurotransmitters from the sympathetic nerves to the muscular coat of the arteriovenous anastomoses due to local cold. This cold-induced vasodilation increases blood flow and subsequently the temperature of the fingers. A new phase of vasoconstriction follows the vasodilation, after which the process repeats itself.[1]
https://en.wikipedia.org/wiki/Hunting_reaction
That vasoconstriction on the skin causing it to shrink is actually trapping heat inside your penis. So if the internal temperature inside your penis is actually Getting warmer in theory those internal tissue like the tunica,CC should be eaiser to stretch and expand. It already had no choice to expand due to the vasodilation and smooth muscle relaxation mentioned earlier it seems