Similar to parenting, where parents carry out their duties as parents, this is where brothers carry out their brotherly duties.
The type of brothering depends on age: if you are an older brother, your duty is generally to embarass your sibling; if you are a younger brother, your duties tend to be to annoy your sibling and follow them around.
1 - My little bro hit me with some younger brothering earlier, so I decided to do some older brothering for payback.
2 - Yeah? So what did you do?
1- I embarassed the hell outta him.