I'm pretty sure that would be your last blow job from her.
I guess it would be cool to see a girl swallow my stuff but I would NEVER ask for it from a g/f. It seems unreasonable to expect a girlfriend to do that. If she really liked to do it I would probably think that was really great but I don't see many girls volunteering for that one. I really like girls that act like equals, not subordinate or superior.