I switch up the grip throughout the workout to make sure I hit every part. I start off with an underhand OK grip. After a few minutes of upward jelqing, I turn my palms face down and do some downward jelqing. Occasionally, I’ll do some jelqs to the sides. I always squeeze behind the glans and stretch my dick out on every other stroke or so.
What kind of grip you use depends on the curvature of your dick and the size.