Counterpoint to 1: Your microbiome is massive. You are constantly emitting bacteria. It surrounds you in a cloud like Pig Pen from the Peanuts comics. The reason you have different bacteria on your face and balls is not because they can’t get from one place to the other; it is because they can’t survive/compete there.

If you’re still hung up about your own towel, have you ever considered the implications of oral sex? How is it too whatever to intermingle your own bacteria upon yourself, but it’s perfectly acceptable to subject your partner to an even more invasive bacterial exchange. And if even that extent of biome crossover was sufficiently meaningful, why doesn’t my face smell like pussy yet?