Hope this will help someone. Not long after my surgery probably 3months afterwards, I bought myself a medical grade pump from amazon - vaccurect. Tried as I may, I could not hold an erection. Several guys on here were adamant I was doing something wrong. The erection was lost soon as I removed it from the pump, with the ring in place! I was subsequently issued with a SomaErect device by the NHS - The result was the same - So I gave up.
In the meantime, I resorted to using a strap-on - this did the job somewhat. I was also prescribed the injections, however I do have a severe phobia with needles and injections, therefore the thought of injecting myself or my wife administering it fills me with dread.
I have woken up on occasions with an erection, but lose it once I think about it. With nothing to lose, I went back to my initial VED, and to my surprise can now maintain an erection for penetrative sex by using the Vaccurect device. I also purchased a vibrating cock ring to spice things up. It does not matter which of the tension rings I use, I don't lose my erection, 15mths post surgery my darling wife can "feel" me again! I also don't know if my erections are firmer using the VED + Tadalafil (20mg) tablet, it however does feel like it.
So I would like to encourage anyone in the same boat not to give up, especially if you are still very early days post surgery!