In my past I've had women get off on me in 4 or 5 strokes after putting it in and I've had chicks that have damn near pulled my hair out by the roots when they got off after going down on them. I've also experienced the "challenge girls" for whom getting off is like a wrestling match and I've worried about them blowing an aneurism before they came, and I've had the "climbers" who work their legs up and down you like a monkey climbing a palm tree.
It's all part of learning what works for a woman. Some women have a natural rythm (the good dancers) and others are kind of 'herky jerky'. When I was in my rock star 20's I rarely worried about getting a girl off and even then only after I did first, because I have high libido and my down time has always been minimal (if at all sometimes). Once I started getting women off first I noticed that their drive actually declined after their first orgasm and their performance lacked when it was my 'turn', but I found that they stuck around me quite a bit more. After I got married I discovered that you can actually get off simultaneously (or pretty damn close), but this comes after experiencing each others rythms. Though she's never stated it, my wife likes the downstroke and requires a good amount of pressure on her ****oris when I'm on the pullback. I figured this out from her getting off while riding me.
Few women actually get anything out of a doggystyle position since there's practically no stimulation to her ****, so when you're doing it understand it's for your enjoyment and she's into you getting off that way. Don't use your fingers to get her off unless that's the specialty of the night. If your girl masturbates, she's accustomed to this and, excluding the novelty of having some guy do it for her for a time or two, you'll probably not get her rythm correct and wont be doing anything she can't do already.
Remember, most girls know how to get off, they just don't know how to get off with you until you put the time in. I had sex for the first time when I was 17 and I've been with close to 50 women in my life, but when you finally find the girl willing to spread her legs for you it's more about figuring out what to do for yourself than what's going to work for her. Not until you're into your mid 20's or even 30's do you pay attention to technique.