Thing is, you can slip by over-ruddering, or under-ruddering compared to balanced flight. If you over-rudder you are set up for a spin if you approach stalling angle (in-spin rudder, high AoA). So always under-rudder.
In other words if you are turning left use right rudder to slip, if right, use left rudder. That way you are under-ruddering. So slipping turns are good!