What RB said. I (usually) use the pump twice daily, pumping up 2 or 3 times, holding the vacuum for a half minute or so each time, then releasing it. We have had no success so far with the rings maintaining a firm enough erection to allow for intercourse. The pump should have a self-limiting vacuum relief valve in it, if it is a medical quality pump, so no harm is done by pumping and holding. Once in a while I will put a ring on and keep it firm while I shower and such, just to keep it engorged for a while. At 10 months, it's still all exercise, and I still can't hold the blood in once pumped, hence no erection. It becomes work and an unpleasant chore quickly, but it an essential part of penile recovery, so you must work at it.
Has the doc mentioned the other 2 legs of penis therepy- Viagra and injections yet? If not, he should be doing so by now, in my opinion. Its a 3 part therepy course for us persistant long term recovery types. Congratulations on the continence, by the way...