Jelqing targets mostly girth, but if done properly, is also beneficial for length and EQ. Combined with stretches it is the recommended exercise for beginners and veterans alike.
Judgements drawn from a single encounter with a female are often worthless as she might have been a size queen or unwilling to show you how pleased she was by your performance, as this would give you power.
"She took it fairly well.” Remember: The point of these techniques is not to build a tool to hurt women with, as it shouldn’t be the point of sex in general :D .
As you probably know, your size is statistically fairly impressive as it is. Many around here even consider it the perfect size.
If you choose to pursue PE (this post is not supposed to oppose that), I suggest you start with the newbie routine, which consists of a warmup, stretches, jelqs and kegel exercises.
Welcome to the forum :D