Tweaking, I have a real issue with using IR - I find by the time I’ve heated the second side (I aim just to directly heat the corpus cavernosum) that I’ve lost a lot of temperature from the already heated side. I’ve experimented with toil foil (not as a hat) with little success.
I haven’t had this problem. I’ve found the heat penetrates completely through, so although one side is more heated, overall it doesn’t matter. That being said, my IR lamp has a large heating plate AND is much more powerful (250W) than what most people seem to have on this site (150W). It’s also got a moveable stand that bends in three places so I can adjust where the heat is coming from very accurately.