Regarding PE I am simply a newbie, but if the techniques used to stretch muscles can be used to PE then I am inclined to say that heat has an important role.
By warming-up soft tissues to be stretched by the application of local heat you may increase their extensibility and may decrease the risk of injury from stretching. Not only that, but also makes the tissues to relax and be more easily lengthen with less discomfort.
There are studies that show that heat combined with stretching produces greater long-term gains in tissue length than stretching alone. And there are studies showing that those differences are insignificant.
Taking that into consideration I gotta say I prefer to warp-up before stretching. The issue is that after warming-up my penis tends to get erected and makes it difficult to stretch. Perhaps, I could try to stretch without warming-up first, but paying attention to signals like pain to prevent injuries. Maybe this is the only way I have to stretch it because everytime I use heat and stretch my penis I have an erection. I also know that the stretching itself increases the blood flow.
One more thing I’d like to add is that some studies have demonstrated that “cooling soft tissues in a lengthened position after stretching has been shown to promote more lasting increases in soft tissue length and minimize post stretch muscle soreness. So, it is suggested to “apply cold to the soft tissues that have been stretched and allow these structures to cool in a lengthened position. Cold may minimize poststretch muscle soreness that can occur as the result of microtrauma during stretching. When soft tissues are cooled in a lengthened position, increases in ROM** are more readily maintained”.
Well, that is what works for the others muscles of the body, but what if all that knowledge is applicable to PE?
And I guess it might be. I know nothing of what I said is new for everyone here. I already read lots of post saying this things I mentioned above.
But it is worth it to bring it up once in a while. ;-)
**ROM = range of motion
Source: Therapeutic Exercise, 5th ed., Kisner & Colby 2007.