What is Stepbrothering?
1.
To rub your scrotum on something, as seen by the scene in the movie "Stepbrothers" starring Will Ferrell and John C. Reily, where Will Ferrell's character rubs his ballsack on John's drumset.
Simaliar to
I just STEPBROTHERED your face.
Pfft. Only
noobs stepbrother after a double kill.
I just was caught Stepbrothering.
See