Many years ago i tried a pump, and it really worked. My penis got bigger, even flacid. The erections got more hard, quicker and longer.
I believe is a good exercise.
Only negative sides were,,
painfull at times, where the pump squeezed the testicles and,
If you overdo it the penis gets deformed and,
It will not take many sessions to your girl have a hard time putting mr bigger in her mouth.