Sistercest

having a realtionship or sexual relationship with your sister's ex

I can't believe my sister is fucking my ex. She's committing sistercest.

Sistercest by lexkatt December 2, 2010

Sisterection 

Becoming aroused from contact, verbal or physical, from one's female sibling.

I couldn't concentrate on my maths homework, as I had a sisterection from the family gathering.

Sisterection by Moses "Sandals" Jackson November 13, 2010

sisterectomy 

The act of removing a sister from your life, either physically or metaphorically. First used in the Simpsons episode "My Sister, My Sitter".

Simpson? Look, we've already been down there tonight for a sisterectomy, a case of severe butt rot, and a leprechaun fight. How dumb do you think we are?

sisterectomy by ubersmith May 17, 2016

Dr.sisterfister 

The man, the pope, the doc, the absolute gamer, a madlad thats has 3 monitors and a bunch of stash of anime girls, what a guy, yeah, oh but I have to warn you that he sometimes will ra-

and someone ship him with audiction, idk who, and idk when but...yes its real

Person 1: do you remember his name?, that youtuber I saw earlier in the streets?

Person 2: oh, the one that carries 2 anime body pillow?

Person 1: yea

Person 2: his name is Dr.sisterfister

Person 1: oh thanks

Dr.sisterfister by Proxley the serwofun caretaker April 13, 2020

sisterfister 

Strictly, one who indulges in a particular form of incest, using only their hand (see fister. Often used as a term of contempt, and shortened to "sissy" on account of their unadventurousness.

See also brotherfucker.

Your brother's such a sisterfister, you know.

sisterfister by Lucifer B September 20, 2005

Sisterfister 

Adjective meaning an alternative, clean version to Mother Fucker

*joey smacking Sarah on the butt
Sarah - "Ouch you sisterfister"

Sisterfister by Hink68PMMF October 25, 2017

Sisterfister 

its the female of rare species called brofister, it was discovered in youtupia jungles at 2017 by the famous scientist felix kelberg pergananet

and always sisterfister!!!!

Sisterfister by RoloxX September 2, 2017