Objectives
There is a saying in Chinese, 知彼知己, 百戰不殆 (zhībĭzhījĭ, băizhànbùdài). It means, "If you know your enemy and know yourself, you can fight a hundred battles with no danger of defeat”. Sexual partners are not an enemy to fight, but they do need to understand each other to avoid harm. Of course, the first step of sexual intelligence is to look back and get to know yourself. But the next step, for satisfactory sex with a male partner, is to study and properly understand 'his body'.
That “Thing” We Don’t Have
Anatomy of the male external genitalia;

- Penis (shaft)
The visible long body of the male genitalia we are commonly aware of.
Inside the penis are two corpora cavernosa and o