It doesn't have to be hard to ejaculate!
My partner of 20+ years is hitting some (hopefully minor) ED issues and turns out this is still possible even flaccid. Having read up about it, it is indeed true that the two systems are separate and a solid penis is not necessary!
For those wondering we are still able to manage some degree of penetrative sex, and this is when it happens. It's admittedy not as enjoyable (he says) and obviously not as fun for me either - although I managed to reach orgasm too due to lots of foreplay.
Well, you learn a new thing every day!