When in combat enemies will attack you. When they do your spidy sense will tingle red. You counter by pressing "y"
So the idea is to get a multi-counter and you guessed, that's when 2 enemies attack you at the same time (tingling red) you press "y" twice to counter both at the same time. Do this 30 times for the achievement.
A great place to get this fast is the combat challenges located in stans comic shop.