Experimenting with cage length

[Papageno]

I'm using my cheap chinese chrome plated cage (to long for me) to determine what custom made cage size I will have to order. For this, I inserted a cut cock cap terminated by a plastic bottle cap in the cage before putting the cage on. By varying the cut cork length, I can try another cage length.
My question then is how short can I go without risking long term problems ? I noticed that for some quite short length, it tends to force black some part of the erectile tissue inside the body.
And advice ?

[_lj_]

check out MatureMetal's website for measurement information

but a quick guide - (Based on my experience of the JailBird)

measure the length from the underside join of shaft and scrotum to the tip of the flaccid penis, do this several times over several days. Being a "grower" I could do this using my middle finger as a ruler, so it was very easy to do, then measure the finger !

Preferably get some plastic or metal rings and find one that just slips along the shaft, touching gently. Measure the internal diameter

If the diameter is right, an erection doesn't really get started, so expansion of length is held back as well as diameter, and there isn't any significant extension. You might be getting that effect because your current device cage is too big a diameter and an erection is developing (in both directions)

Given the right measurements, there is very little backward expansion.

[WifeIsVanilla]

My advice and experience are exactly the same as _lj_'s.

[attentive_husband]

Is it correct to say that I should fully fill the cage at my smallest? Not tight, but comfortably filling it?

Also do I measure length from the base at the top of where my penis joins my body? Or the bottom?

[Locked by LRC]

Is it correct to say that I should fully fill the cage at my smallest? Not tight, but comfortably filling it?

Correct.

Also do I measure length from the base at the top of where my penis joins my body? Or the bottom?

If ordering a custom manufacturer refer to their instruction and no others. If it's an off-the-shelf device it's a guess but I think it's usually on the bottom.