When in doubt, put your bro bun on the vertex
With a man bun, you’re truly free to tie it wherever you want on your head; there are no rules set with regards to the position of your bun on your head. Your hair length, however, will affect which type of man bun you can style, whether it is a semi man bun (only hair on the top) or a full man bun (all hair on the head); read my man bun length guide to get an idea of the hair lengths needed for your man bun as well as where on the head you can style each of the buns.
The natural position of the man bun? The vertex
The vertex is a pretty interesting part of your head: it’s where cowlicks typically form, where male pattern baldness starts and where the man bun naturally sits. The vertex area is also known as the crown (of your head); physically, it’s the back of the top of your head.
When styling a man bun, you will be sweeping back the hair on the top of the head, and thus you will end sweeping back right at the vertex, hence the vertex is the natural position for a man bun.
Never mind that you can position your bun anywhere you want. However, if you are a newbie to the manbun, then I highly recommend you t first start as explained above and let the bun sit on your vertex. The actual sweeping motion is very instinctive and you will find yourself easily holding all the hair top of your head with ease right at the vertex area.
If you have any questions, let them know below!