Blow job etiquette...what do guys prefer?

I love sucking cock and I love watching videos of girls suck cock, but there is one thing that girls do totally wrong. Too many girls use their hands on the shaft. When I get a guy to cum, it is because of how I used my mouth. It is a blowjob, not a handjob. If I use my hands at all it is to hold his balls. God, I love balls, but that is another topic altogether. I am fine if a guy pulls out of my mouth and uses his hand to finish jerking into my mouth or face, but I make it a point to keep my hands away.

Guys...is it ok if a girl uses her hands when she gives you a blowjob?