Hi James, welcome to the forum :)
Wet jelqing is for both length and girth, depending. To target girth gain, most tend to jelq with a higher level of erection(around 70-80% erection seems to be the average). To target more of a length gain, the standard is usually jelqing at lower erection levels(around 30% give or take).
You don’t have to hold behind the glans with one hand while you perform a rep with the other. At least, I don’t. But to each his own.
As far as how “I” perform a jelq for length… While my unit is “plump”(30% erect, give or take), using baby oil with vitamin C, I use an over hand grip at the base(bone pressed grip), and I ‘milk’ my penis moving upward with my grip, keeping just enough pressure to force the blood up toward the glans while pulling/stretching at the same time. When I get to just below the glans, I pause and hold in a stretch. Keep in mind that the whole rep is pretty mild. I go by feel. No pain should be felt at all. I don’t baby my unit, nor do I beat it to death. At the end of my jelqing session, my unit feels ‘worked’. Very nice feeling indeed :) .
Exercise caution when determining how tight your grip is, especially if you are new to this. You don’t want to injure yourself as I have read of others doing so before. Start out light, then gradually increase your intensity as your dick becomes accustomed to the exercises.
I would suggest starting with the newbie routine.
Just my 2 cents ;) .
Good luck!
Ironhammer
Start- May 2007: BPEL 6.5, NBPEL 5.5, EG mid 4.75, EG Glans 4.5
Now- July 13th 2007: BPEL 7, NBPEL 6, EG Mid 4 7/8, EG Glans 4 7/8
"You can't build a reputation on what you're going to do"- Henry Ford