Sis spotting

When your friend has a crush on your sister

A bro are you sis spotting right now not cool man

cous-sis

A cousin so close and tigh with you, they're like a sister. They always have you're back and you can tell them anything.

The sister you never had

"Do you have any siblings?"
"No but I got a Cous-sis"

Si Yao

pourquoi tu cherches mon nom? tu m’aimes?

Si Yao est tellement belle OMG

si yang

A person who does not tolerate naughty things and is wholesome on the outside but is secretly curious about naughty things his friends know, searches it up on the internet and immediately regrets it.

John: "Yo johnny do you know what a rimjob is?"

Johnny: "Nope."

John: "Search it up then*

Johnny: "wtf is this"

John: " Hahaha you are just like si yang"

si futz

Pig pussy in pa dutch

I would like to order some si futz and turnips

crissa's sis

a christmas cake

crissa's sis is a christmas cake

sis science

Feminine based pseudo science. Common beliefs with no real basis in science but are practiced and passed down like sacred old wives tales and "chick wisdom"

Also see bro science

My mom always told me that emu oil makes your hair grow. I have no idea if that true or just some old sis science.