Okay, About the difference a pump makes.
I know it's a while since someone asks, but I'm slow to respond to certain questions, DWI.
I don't get hard often.
This is "probably" due to a combination of low blood-pressure, chronic pain, chronic fatigue, and depression.
This means I do actually have a chance of comparing erection to erection as they're "maybe" twice a week.
The difference between "flaccid" and "hard" has been expanding far faster since I started pumping.
There's a clearly visible/noticeable difference in size now, whereas about 2 months ago, the difference was almost solely one of "how squishy it is". (I am aware that I'm wording things poorly, my English is less good at early morning without sleep than it is in early afternoon with sleep, DWI.)
This "might" just be the T, but the damned thing gets harder, longer, a little wider, and sticks out a fair bit more now when hard than when not hard.
Seeing as I'm too busy being all

and playing with my husband every chance I get in that particular state, I haven't brought the measuring stick out for checking exactly what the difference is, but I'm getting increasingly interested in doing so.. for rather obvious reasons. (I'm a dude, I wanna know the numbers and brag where possible!)