This might have been asked before, I'm too lazy seacrh through forum.

But anyway, I found a site (finnish, no use to link) that has an evolved version of jelq. Basically it's the same than normal jelq, but the site suggest that you should first make one pressure grip the to bottom of the penis, so blood doesn't circulate out from the penis (I suppose) and it also helps retaining semi-erection. After that you just milk it from base to glans, but not over, like in regular jelq. The site seems to be sure it's inproved version of the regular jelq.

But I'm just wondering, can a tight pressure grip actually harm your penis? There is also another excercise done with fully eredted penis, and also needs to pressure grip to keep at full, but it doesn't really need that tight grip to keep it fully erected, so that sone should be okay?