system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it easier to whistle after licking your lips?

After wetting your lips, it is much easier to get a good tone and more accurate pitch. Why is this? Does saliva work as a lubricant of some sort?
gpt
Not a lubricant, a sealant.  It's the same principle behind moistening a suction cup before trying to stick it onto something.

When your lips are dry, they don't fit together as perfectly.  There are tiny nooks and crannies that can let air pass by.  When you try to whistle, air escapes through these and messes with your pitch.

When you lick your lips, you fill those nooks and crannies with saliva.  Water has a high surface tension, so it likes to cling to itself and to surfaces.  When you press your lips together, all those extra escape passages for the air are blocked by the saliva.  The air only goes where you want it to go, and you get good pitch.