Ashling, Flame Dancer rewards a turn built from several instants and sorceries. Each magecraft trigger makes you discard, then draw. The second resolution in a turn also deals two damage to each opponent and each creature they control, while the third adds four red mana. Cheap spells and copies can turn that sequence into a productive burst of filtering, damage, and mana.
The count tracks resolutions of the ability, not simply how many spells you intended to cast. Copies of instants and sorceries also trigger magecraft, making cards such as Reverberate useful for advancing the sequence. After the third resolution, further triggers still filter your hand, but they do not keep producing four mana every time. A fourth trigger is not another third trigger.
Ashling also lets you keep unspent red mana as steps and phases end. That makes the mana burst easier to use across the turn, and it can preserve red mana into later turns while she remains on the battlefield. Removing her can change that plan, so holding an enormous reserve indefinitely carries a risk.
In a dedicated spellslinger deck, low-cost interaction and draw spells help reach the second and third resolutions without consuming the whole hand. Discarding first can also stock the graveyard for later recursion. With an empty hand, you still draw when the ability resolves, although you will not discard a card. Plan the order of your spells so the damage arrives when useful and the red mana arrives while you still have something worthwhile to cast.
