Someone who has to pull his stepsister out a washing machine
STEPSISTER STOP GETTING STUCK IN WASHING MACHINES! stepbrother screams
by Iwillkillmyselfwithpeanuts September 10, 2020
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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 teabagging.
I just STEPBROTHERED your face.

Pfft. Only noobs stepbrother after a double kill.

I just was caught Stepbrothering.
by Ol' Betsey April 21, 2009
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when one man fingers a chick that another man has had sex with, then the two men are eskimo stepbrothers. similar to eskimo brothers
Rick fingered a chick last night and later found out that his friend James had banged her a month ago. Rick and James are now eskimo stepbrothers.
by skirtripperclubprez September 5, 2011
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The title given to someones brother of sisters boyfriend if they're not married
Juan: Who's this Harry geezer?
Tom: Oh he's my sisters boyfriend, that makes him my stepbrother-in-law
Juan: Surely he's your stepbrother?
Tom: Nah fam, he's not married to my sister
by why_am_1_doing_this May 1, 2019
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