To rebalance your humours, medieval doctors would pop leeches onto your skin and let them suck your blood.

为了重新平衡你的体液，中世纪的医生会把水蛭放在你的皮肤上，让它们吸你的血。

Unless you know the person intimately or very well - that's fine, but in human nature, we don't really come and leech onto someone or sit really close to them.

除非你非常了解这个人——这很好，但在人性中， 我们并不会真正地靠近某人或坐得离他们很近。