In trials, I found that using the pump would puff me up quickly enough anytime I used it, but my erection didn't last long if I didn't already have a specific use for it in mind...All I can say is that it's easy to use and it worked effectively.
The most helpful critical review
Puuuump it up...Puuuump it up
This penis pump is solidly built...and it does work. Seeing my own cock as larger than life through the plastic cylinder was a definite aphrodisiac. However, removing your penis after you're finished pumping and ready for some action leads to loss of most of the volume gain while your penis is under vacuum. Overall I'm glad I tried this, and I'm going to modify the rubber sleeve (cutting an inch of so off) in hopes of making withdrawing my penis easier.