It has two meanings!
1. A sexuality which means you're attracted to
suicidal people like Sayori. Hence the name, KYS-exual.
2. A sexuality which means you're attracted to the
cartoon character Kyle Broflovski, and anything that resembles him.
For example, you can't date someone, if they don't look like Kyle. If you want to impress them, buy that fucking ushanka.
Meaning 1:
Person 1 - Oh my god, you're suicidal?
Person 2 - Y-Yes..?
Person 1 - I'm KYSexual, so we're dating now,
I love you.
Person 2 - Really? Wow, that makes me want to live again!
Person 1 - ..I think we have to break up, fuck you, bye!
Person 2 - (is dead now)
Person 1 - WHY WERE YOU LYING I LOVE YO-
Example 2:
Person 3: Hey I kind of..
I like you.
Person 4: You have the ushanka, orange jacket and
everything~
Person 3: Okay, and?
Person 4: I'm kysexual~