Sisfuck 

The sordid act of sodomising one's own sister.

Mendes likes a sisfuck every now and again.

Sisfuck by Roger Jackson March 22, 2003

sitfuck

having sex while sitting down

Did you see that shit they were sitfucking while I was eating my sandwhich.

sitfuck by Matt June 17, 2006

Susfuck 

The term susfuck is derived from the word sus, meaning to be suspect or suspicious, and the word fuck. It means that something is suspect as fuck.

At a Trump rally: “Yo, I’m not sure if that hair is a toupée, but it’s susfuck.”

Susfuck by Dahktdurhh ElB December 2, 2022

susfuck 

The act of being fucked ironically

Caught down real sussy

I want to be susfucked down wholesome🤤 my friend said this I swear

susfuck by RdAjx October 11, 2021

Sirfuck 

When the fuck is so sir it becomes a sirfuck. It is a word that typically faggot like to use.

Come on sir, like what the sirfuck.

Sirfuck by The most Epic gamer October 26, 2018

sifuck

use this word with caution where people think your actually saying it/ the meaning is when you your about to say son of a bitch but also say fuck you so you say sifuck you your welcome

you sifuck-er that was my cookies you asshole you son of a sifuck you die in a fire you cunt and to that bitch you married

sifuck by available_available..sup human September 15, 2020