Here is the run down from what I was told, I personally don't have much experience:
Straight girls - high chance of smelly... and dirty a..
Bi girls - high chance of super clean as they know the feeling of a smelly...
Girls 18-23 more likely to have smelly...
Girls who strip or hook but dont do drugs or get super drunk - smell great
Girls who strip and hook but do heavy drunks / drink heavy - super smelly
Guys also must take into account that women are humans, if you are out and about all day dont expect to come home, pull their pants down and smell anything good
Same when guys get dramatized from a nasty anal session with their girl (where you are the top lol), biology does not care how much both of u want to engage in anal sex, if there is a lack of preparation there will be shit all over the place
Last but not least be sensitive about this stuff, some women have conditions that increase the chances of foul smell, there is no nice way to address this, at least I dont know of any.