IF it doesn't smell right, don't go down on her. It could just mean that she has been sweating alot recently and needs to shower, but its also a sign of a yeast infection as well as some STD's. I love going down on a girl, but if it doesn't smell right, it isn't going to happen.
I am not sure if there is any correlation but the by far the worst smelling pussy I have been with was an ex who used to g-spot all over the fucking place...and I mean everywhere! What should a pussy smell like? Like flowers of course.