I am not aware of any scientific research that has been published in peer-reviewed journals that suggest any of these methods actually work to make semen or vaginal fluids taste sweeter or generally more pleasant. That said, I am also not aware of any research that discounts these methods – in other words, they are pretty much untested and unknown.
Each woman’s vaginal scent and taste are unique to her. So, although it is common for vaginas to taste or smell a bit yeasty, acidic or like sour milk, a woman’s vaginal taste can change throughout her menstrual cycle or in response to her behaviors or her health.
Although sperm are quite small, they typically do not make it through most types of clothing unless, of course, both partners were wearing mesh clothing or other clothing with large holes in it, or if they pushed their underwear to the side or were wearing thong underwear and thus somehow had direct genital contact.
It can be difficult to talk to a sexual partner about genital odor, particularly since many women and men are sensitive about how their sexual partners perceive their bodies. People generally want to feel attractive, desirable and sexy to their partner – and feeling as though they smell bad can make it hard for them to feel desirable.