system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why can people drink coffee at the same temperature that can cause burns to the skin?

I know everyone has a different preferred temperature...

If I spill coffee on myself, it’ll hurt like hell, but I drink that very same coffee with no issues. Why?
gpt
Your mouth makes saliva, which is mostly water (which takes a lot of energy to heat) and at your body's temperature.  Mixing 10 mL (2 tsp) of very hot liquid and perhaps 20 mL of saliva, means that the very hot liquid is quickly cooled.  

Your skin has no saliva, so the heat from your coffee transfers to a small part of your body, dramatically raising the temperature of the affected area and giving you a burn.