So just from playing at low levels I see the main application of sucker punch would be to disrupt ice witches from freezing an area. My question is how exactly should I use it. The approach of going up to them and trying to use the ability when they start channelling rarely works as you get frozen before you have actually carried out. Could anyone advise me as to what other key applications it has and how best to go about using it?
Cheers

Hi mate,
I'll try to be as precise as I can but it might not be clear since english isn't my native language.
Maybe you're not aware of that fact but the more the frost witch channels her freeze the faster the ennemies will be frozen (stacks apply faster after 4 secondes channeling or something like that).
With that in mind you mostly won't have the time to disrupt if she started channeling a while ago except if you have some rage stacks and frenzy + attack speed amulet but yeah you'll mostly get frozen. You will have to guess when the witch will start to freeze to use you sucker punch right when she starts channeling the spell. However sucker punch isn't only good vs ice witches !!!
With it you can :
- Intterupt potion drinking as it is considered as a spell (but you really need to be fast because the animation of the potion is slightly longer than your sucker punch but timing is tough)
- Interrupt another bers using sucker punch / tank using shield bash that is trying to interrupt an ally frost witch freezing
- Make a sister of fire automatically switch to close combat fighting (since the fireball is a spell which could be seen as a stance --> when in close combat stance only using her staff and when switching to fireball, the auto attacks becomes ranged. Using your sucker punch will cancel that stance and force her in close combat)
-Interrupt Vortex of War / Crushing blow / skyfires / etc..
- AND the most important effect of this skill --> Draining the ennemy endurance pool to replenish yours in order to stop them from sprinting away from you and enables you to sprint or land a power attack on a walking target.

I intentionnally didn't put all the uses because you will see that it's so much better to discover the uses of a skill by yourself. You'll come up with tips of your own afterwards and maybe help another new player but you now have the basics of this spell
Good luck mate, enjoy