If you start to skid should apply a quick pumping motion your brakes if have anti-lock brakes?

No, if you have anti-lock brakes (ABS), you should not apply a quick pumping motion to your brakes if you start to skid. ABS is designed to prevent the wheels from locking up and skidding by automatically modulating the brake pressure. If you apply a quick pumping motion to the brakes, it can interfere with the ABS system and make it less effective. Instead, you should apply firm, steady pressure to the brakes and let the ABS system do its job.