Vacuum hanging help

Hello people, today I started hanging with a vacuum hanger from Total Man.
I am not wrapping, I have seen on their website a strategy where you put water into the cup, get all the air bubbles out and your glans is protected.
So I do this:
1. A little bit of tape on the shaft, just under the glans
2. Add a double silicone sleeve over that tape (I need it to "seal" the cup).
3. I add warm water into the cup, put the glans in, seal it, pull silicone sleeve over shaft
4. I vacuum the air out of the cup and start hanging

I did 3 x 15 mins, removing device between sets, to check how it looks since it was my first time hanging
Just when I remove, glans is a little purple-ish and cold. It goes back to normal in 2 minutes.
Is this normal? Purple cold glans when vacuum hanging? Or am I doing something wrong
Because if this is not normal, it means the exercise is also not very effective, if the glans takes too much stress.
Or is the glans problem because I have to use double sleeve under the glans and it might semi-cut circulation.
I hanged with 1.5kg

Yes, that’s normal. At least, I get the same results. You can wrap with hot towels or use a heat lamp, but be careful not to get things *too* hot; it’s not erect, and circulation is low, which is why it gets cool. That also means there’s not much blood flow to pull away excess heat. If you overheat, the results will feel something like sunburn.