Penis Extender Basic Questions

Hey, so I’m wondering about proper extending technique. I have a really sensitive head and shaft, and when I put my X4 Extender on, about 85% of the time, I get an erection. I’ve read doing jelqing and other exercises with an erection can increase girth but decrease length. Should I take off the extender every time, I get a boner with it on? Does anyone have good techniques for reducing erections when wearing the extender? Also, any other tips that you wish had been told to you when you first start extending, would be welcomed! I literally am on my second week with an extender and PE.