Debouncing/Stabilizing power supply rocker switch?
As Debounce you can add a cap. But a little better is an RC Lowpass, because a cap alone causes big currents when turning on which could harm your switch (mostly only if the cap is a little bigger). 

If you need a fast changing Signal then you can put a schmitt trigger after the lowpass and an unloading resistor parallel to the capacitor. This is a luxus version, but more proper than just a cap. 

If it's a hobby project try it with a cap but if the switch needs to last long time try the other one with the low pass.