I jelqued seriously for 6 months last year. I adhered to a rigid schedule, working my way from a slow pace to a very hard pace with on and off days .
When I felt my cock was ready, I began pumping for girth, and again adhered to a rigid schedule. My cock began to pump up when flaccid, and it hung a bit better.
With an erection, there wasn't much of a change, though it felt firmer. I stopped because with 3 kids in the house, I had NO alone time to spend jelquing, usually 20 minutes a session.
My wife didn't feel anything different at the time and I don't think I gave myself enough time to see any lasting benefits. Now, a year later, my penis is the same as it always was. I would like to start agaiin, but it's a time issue.
Please be warned, if you start, go easy...A lot of guys, myself included, go at it pretty hard at first and end up hurting themselves. I had a condition called a "thrombosis vein". I put too much pressure on my penis during the first 2 weeks of jelquing and the main vein that runs up the penis to the head was engorged and hurt like hell!
My vein runs along the side of my penis and crosses over behind the head ,below the ridge. When I became in inflicted, it looked like I had a second ridge to my head, and did I mention it hurt !
It took a couple weeks with warm compresses before it was subdued and a couple more before it was gone for good. If you start, start slow, and be prepared for months and months of dedicated service.