Bundled stretches: safe or not?

I’ve been doing PE off and on for years, and I’m well conditioned for advanced stuff. I can do a bundled stretch pretty close to two full turns (720 degrees of rotation) although it’s definitely stressed at that much.

As best I’ve heard, this is mostly a warm-up exercise to “break down” the tunica to get it ready before pumping or jelqing.

But I have to ask if it’s really safe? While most of the posts I’ve read (in other forums too) talk about it’s benefits, I’ve also seen posts saying it can cause serious damage.

What do you guys think of it strictly as a warmup? Is it OK to give it enough turns (720 degrees rotation) to the point of some tension/stress? Or should I play it totally safe and never go beyond one full (180 degrees) turn?

Are bundled stretches safe or not?