I don’t know what sex stores are like where you are. (Where are you? Australia?) But I see these for sale in my local Seattle sex shops displayed somewhere around the cock rings.
I mostly use the device for near-erect jelqing. I place it way down around the base, and then just do an OK grip underneath it and jelq upward. It really helps pump things up. It’s also really works when doing the same basic thing with a power-jelq.
Im in PA, but I saw this company online. May have made a mistake ordering from them. Anyway, I wanted to buy a “condom lock” because sometimes during intercourse the condom I have on slips a little bit because I lose some of my erection. But I realized that if I squeeze the base and pump my penis a few times during a break during intercourse it comes right back. So I wasn’t sure if a tight cock ring would do the same thing by holding the condom on and keeping me erect. This product in the above post looks like something that could help in this area.