system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that if you lick or spit on something, your saliva smells pretty bad, but it doesn't necessarily taste bad to kiss someone?

And another person's mouth doesn't have to smell bad up close either.
gpt
Dental student here. You don't smell the odor compounds when they are dissolved in the saliva. It is only when the saliva dries up, like when you lick the back of your hand, that you can smell them. That's why you tend to smell bad breathe when someone talks; the moving air dries up the mouth and carries the compounds toward you.