Why do some forums claim jelqing is dangerous?

[sensaZn]

As the title mentiones

 

[-SIM-]

As the title mentiones

Probably because of this.
Post in thread 'Erect Jelqing Dangerous??' Erect Jelqing Dangerous??

Do C-Jelq's on the side of your penis instead.
Some have pushed to hard on these nerves and veins/arteries and have inquired themselves. But they blame the exercise. Never blame the exercise, if you are abusive to your own penis.

Look at this as well.
Post in thread 'girth work' girth work

 

[oldandlively]

As brother SIM pointed out, it's actually the method of jelqing and improper grips. Under erection, the veins and capillaries that supply your blood under natural constriction are under pressures. Those who just jelq blindly further pressure the veins and capillaries and cause thrombosis due to overpressurization without first preconditioning the veins and capillaries. It's like working 200lbs of weight as a newbie without first conditioning the body to deal with the weight loading that exceed the body potentials.

 

[DLD]

Jelqing is completely safe but I suggest using the Slow squash jelq. So much more expansion so much faster