I'm trying to get slime balls to make stick pistons. Now are slime monster turn on ? or can some one make some ?

You Can't Craft Slime Balls But Slime Spawn In Vast Underground Space. Whereas Is The Slime Is Turned On Or Not I Am Not Clear About It

slimes are on, and they only spawn in certain chunks.

Source(s) i have 3 stacks \o/