How do you know this ? Sure you can do erect jelqs. You just have to condition your penis well enough to take the amount of stress and pressure cause by this exercise.
I don’t do erect jelqs becase they don’t work for me. If you read my post well you would see that I said it works for very few people (I had you in mind). But let me ask you, would you tell a newbie to do erect jelqs?