dude, i dont think its worth the risk when it comes to your penis...there are better ways to get girth...plus from my experience erect jelquing/clamping goes away after a while and leaves you with a deflated semi erect penis that cant maintain a strong egnough erection, it took me like a solid year and a half of not doing anything to fix what i did to myself from erect jelquing/clamping
heres a little story about when i was clamping, i was with this girl, and i was way into clamping/ EJing ..she was givving me head and i couldnt get a full erection, so i said fuck it, and i did some clamping while she was blowing me, her jaw got mad tired, but when i went to fuck her i lost like half my girth, it sucked...