Everyone has a natural scent... some people good, some bad, boys if you think pussy is the only thing that has a smell you haven't given a bj to a man with smelly balls (even after they've been cleaned some still have a pungent musky smell)... and some you can't really control.. some cultures even just have specific smells that tend to be distinct to that culture... even when fresh out of the shower, some people just have that strong natural scent. (bo)
I tend to think if it smells bad it is natures sign there might be a problem. but it could sometimes just be attributed to health in other ways too, undiagnosed things like diabetes, eating habits, natural reactions to external environment.. there is a lot that can affect someone's natural odor..
it is also a source of pheromones', some can be strong and still smell good.. personally I like my scent when I am turned on, it makes me and some around aroused subconsciously, the whole world is a reaction of chemicals and chemical responses some we don't even know about or realize it is there.
Fishy is a sign of a bacterial thing or even just yeast infection. It is a little embarrassing to be told you smell bad, but some girls don't realize they have a health problem until the scent is brought to their attention. or taste I guess, but if it smells bad I don't know why you would still go in for the taste test
and some condoms are the culprit to the smell, it could also be a result of friction healing because not enough lube was used... like I now carry my favorite lube with me everywhere I go, because the lube on a basic condom just doesn't seem to react well with my natural body chemistry and was causing reactions. I also stay away from certain brands of condoms for that reason too.. (lifestyles condoms). some girls are also just learning their bodies and what works for them and their body chemistry...
chemistry class is hard for a reason.. 1 element out of place can vary a great deal in the overall outcome.