Well in my case, I must say.
I fit the extender while being erect. I push the device just under the glans..
Tighten the strap a little then wait for the shaft to slightly deflate, then tighten it completely while inflating the head.
(I use a sleeping bag strap (with non-slip buckle), so it’s very easy and adjustable as a charm)
In other words, I put it on a 80% hard on. And *then* the penis goes to “flaccid” by itself.
Never had any problems and settling the extender takes me less than 5 seconds.
That being said, I do sessions of 1h to 3h30 without problems.
But 2 hours session are better as I’ve come to notice. (A little bit less painful)
I do from 4 to 6 sometimes 7 hours a day.
1h30 on day off.
And I’ve read earlier about blisters in this thread.
That either mean that the strap is too tight first of all.
And/or that you had an erection while wearing the extender.
Which is a “No no”.
I hardly recommend to use a non-slip buckle strap, which means that loosen the grip of few “mm” under the glans
Will be done in a fingertip motion if you happen to have an erection while wearing the device.
Then blisters will be avoid and become things from the past. :)