Spam press melee 4 times while standing still to strip 120 armor (30 per press) from the Eidolon.
This strips 120/125 on Terry, 120/130 on gaunt, and 120/150 on hydro.
If you accidentally shoot a fifth time, or melee slam into the Eidolon when its on the brink of its armor (like teralyst), you will overstrip it, lessening the damage boost that radiation does the eidolon, and increasing the electric damage it takes.
Overstripping is only good if you want vs to shoot limbs and take them, due to the eidolon now taling bonus electric damage, which shooting through a shield gives, but is normally otherwise not recommended.

High noon can theoretically strip more armor from the Eidolons (144/150 max) however high noons interacts weirdly with speed mods causing less bellets to shoot with higher speed, meaning your speed mods, including berserker (which procs randomly while you strip) cause you to either strip less or more, leading to it being inconsistent and reliant upon whether you have beserker and [Volt] speed active when you attack to figure out how many attacks you should do to strip. Aside from being inconsistent, its much, much slower than [Bullet Dance] because you cannot spam it, you have to stand still, attack, wait for the animation to end, then attack again. In addition, the 120 vs 144 strip is almost never going to change a damage breakpoint from two tap to one tap or vice versa, it will never affect meta snipers, scarcely affect pistols, amd only very occasionally affects meme weapons.

The free two slots are for whatever you'd like to add, personally I use a speed riven and [Dispatch Overdrive], which I sometimes proc on the vomvalysts at logdash, up to you, and honestly you don't actually need any mods on it other than [Bullet Dance] and [Shattering Impact], since [Bullet Dance] is unaffected by speed in terms of how much each shot strips, its just qol.