What is the best way to ask a girl for a blowjob?

I think that you should let your girlfriend decide when she feels comfortable doing it.  You could ask her nicely if she would want to go down on you, but to make her feel like she has to do it, or that she would be disappointing you by not doing it, isn't nice.  It's not the most pleasant thing for a woman to do.  Some women end up even liking it, but many don't like it at all.  You could also go down on her first.  That is usually a sign that you are at this stage of the game and you would like to receive oral sex too.  You could also always talk about it... to see how she feels about the subject.  Good luck.

It's rude to ask a girl this. If the girl you're with wants to do it, she'll ask you if it's ok. Don't be the one to bring it up. Let the girl you're with make the move.

If you are in a relationship, then you should be comfortable enough with one another to communicate openly. It goes both ways. If you want her to pleasure you, then you need to show her how much you want to make her happy as well. Ask her what she would like and what you can do to make her feel as good as possible. When she sees how willing you are to pleasure her, then perhaps she will want to make you feel the same way on her own. If not, after asking her what it is she likes, you can discreetly slip into the conversation how good it feels to receive oral sex. You can even ask her if she minds and/or enjoys giving it. Make sure that she does not feel pressure when you discuss it. Make it as casual a conversation as possible. Good luck!

The best way would be "naturally."  This type of activity is a normal response.  Just like the hugging, kissing, and when the right time comes, it will play its role.  It's not a good thing to ask.  No!

Try eating her like there is no tomorrow...Learn the joy that is woman. If youre lucky, she might want to make you feel good too. The key to being a good lover is to genuinely strive to satisfy your woman sexually. If you do this, you will often find a wonderful lover in her....one that wants to devour you. Women are very sensual beings. 

 If you want to "get" then GIVE.

Hi,

     If you are a gentleman, you are not going to ask her to do this.

If she really enjoyed your performance, she probably will give you back the favor.  You may be pleasantly surprised.