Why does Zhang Sheng block the high temperature when he is cold?

If the weather is hot or cold, I like Zhang Sheng. The first "eyes" on Zhang Sheng are Zhou Gege and Gao Ruohan, both roommates. They are hypocritical, enthusiastic, active and constantly fighting with each other. In order to resist the "attack" of high temperature and cold, Zhou Gege had to send his best friend Song Nuan for "personal protection".