Why do things cool down more slowly if they are wrapped?
Whatever it is wrapped in slows the loss of heat. It acts as an insulator.
To cool down, people need to sweat, as when it evaporates it cools the body down. On dry days, it is easy to evaporate, as there is little water vapour in the air. On a humid day, it is harder for the water to evaporate as there is already too much water vapour there. As less sweat evaporates, it takes longer for you to cool down.
"Cool" is a slang term meaning first-rate. You could say "That's really cool," or "He's cool." Here are some sentences with other meanings of the word cool. The evening was cool, though the day had been warm. That hot metal will cool down slowly A cool breeze wafted through the room. He gave her a cool greeting and brushed past her.
Anything that is warmer than its surroundings will transfer heat to them and cool down in the process. Lava from a volcano transfers heat to the air, which then carries it away. Underground magma transfers heat to the surrounding rock. Since rock is a poor conductor of heat the magma will cool much more slowly than if it were at the surface.