I purchased a heat vibe and I highly recommend it for anyone who is concerned about their penis feeling cold during stretching or if you want to speed up your progress. There is evidence that heat and/or vibration will speed up your progress, in other words, whatever tension setting you're at, it will be like you're stretching at a higher tension or if you stretch for your regular time, it will be as if you've stretched for a longer length of time.
Once switched on, you hold the (-) button for about 5 seconds to switch on the heating function. There is only one temperature setting and just like the regular vibe; 10 vibration settings of different speeds
Vibration with heating uses more battery than vibration only, so to conserve battery I like to use the heat for the first 10 mins and then I switch off the heat. I'll then attach the vibe with the heat pad on the underside of my penis and let the residual heat dissipate. After 5 minutes I'll switch the heat back on for another 5 minutes vibing on the underside. I'll then put the vibe on the top side of my penis for the remaining 10 minutes, switching the heat off after 5 minutes to do the last 5 minutes of my stretch allowing residual heat to dissipate. Penis still feels warm after removal. I'll then put it on recharge during my 10 minute break.
I was using the regular vibe and after I switched to this new heat vibe, there was one or two sessions where I had to cut my second half hour set, short. During my second set I felt a sharp pain I'm familiar with - the blister warning pain, I reduced tension and still felt some discomfort so I immediately stopped training. Thankfully no sign of any blisters.
Just because there's no sign of external blistering, it doesn't mean there isn't any internal damage so I took a day off to recover.
This experience to me indicates the heat vibe is working effectively, speeding up my training progress.
If you do start heat and/or vibration stretching, I recommend starting at a lower tension than usual and working your way up slowly. Blisters only hinder your training. A dull ache is okay but stop training the moment the pain feels sharp and take a day off.
Photo shows the heat vibe on the left and regular vibe on the right. Having two comes in handy; a fully charged back up should one run out of charge. I tend to use the heat vibe for stretching and regular vibe for pumping, which I hold up against the cylinder.
This is my experience, with my anatomy, 'your mileage may vary'.