In article ,
aemeijers wrote:

Nope, they build in a little hydraulic or air bladder system, with a
subcutaneous pumping bulb and release valve, to make the mockup sort of
function. When it breaks down, I don't think any home DIY repairs are
possible.
(Apologies to the group for prolonging a very juvenile thread)

This was the major treatment for ED BV (before Viagra).