sit-down

Among some lower-socio-economic segments of society in the South, a polite way of saying "using the toilet to defecate", which is generally considered much politer than more common expressions such as "taking a shit".

Student/inmate in a juvenile reform school to his dorm supervisor: Can I use the restroom?
Dorm supervisor: Do you just need to pee or do you need to have a sit-down?

sit on the floor

sitting on someone's genitals

want to sit on my face? "Can I sit on the floor first?"

sitting black

Sitting, in preferably your car, with your seat leaned back so that if you stick your hand out you can barely grab the wheel with one hand.

Yeah man, got so nervous driving today I had to drive sitting black

sitting ass

sit ass - verb - be unproductive.

Possibly a shortening of "sit on (one's) ass".

Just because I am able to figure out shit above and beyond does not mean that I should be required to so that everyone else can sit ass. I am very good at sitting ass, too.

Ankle sitting

Ankle sitting refers to a type of sitting where a person is in a chair, and has one of their leg folded over the other in a way where the ankle rests on top of the knee.

This term was coined in 2024 by youtuber project y.b.t.f.c., also known as Wiz.

A: What's your favorite sitting position?
B: Definitely ankle sitting. I love leaving no room for other people when I'm in public buses.

Sit Is Firm

A phrase from the 1800s that expresses ultimate respect for handicapped people.

Oh no worries sir, sit is firm.

Sit chilly

Means don't move, freeze. Stay quite!

Things may get crazy, just sit chilly and you will be fine.