What to do against shieldbash/headbutt/etc combos?

What do you do when the enemy just spams you with light attacks with shieldslam/headbutt combos? I try to block/parry the normal attacks but what's the best defense against shield bashes from valk and warden when you're pummeled?

Dodging? Can you parry a shield bash? If I get hit by an attack, is the shieldslam guaranteed?

This goes for all combos where some moves have the orange glow I guess.