The mechanic
Senna grows from souls dropped by units dying near her, and only she can pick them up. A minion she kills herself almost never drops one (5%), a minion killed by an ally does far more often (32%), and cannons always do. So she wants her allies to farm normally while she stays close enough to collect.
Why it needs saying
Everyone assumes Senna needs to take farm, and it is the opposite: minions killed by her allies are what feed her souls. Without a word, the ADC either hands her the wave thinking it helps, or blames her for hanging around.
When you play them
- team chat
what you type
farm normally im just taking souls
in full english
Farm normally, I'm just picking up the souls.
the context
"Souls" is what players call Senna's Mist. This line settles the farm question in the first minute: contrary to what everyone assumes, Senna does not want the last hits. A minion she kills drops a soul 5% of the time, one her ally kills 32%.
- team chat
what you type
wait im grabbing souls
in full english
Wait, I'm grabbing the souls.
the context
Souls do not stay on the ground forever. Before backing or leaving the wave, Senna asks for a moment: that is her late-game power lying on the floor.
When an ally plays them
- team chat
what you type
let senna get her souls before b
in full english
Let Senna pick up her souls before we back.
the context
"b" alone reads as "back". Coming from a teammate the reminder lands better than from Senna herself: a Senna who leaves souls behind walks back weaker than she should be.
When an enemy plays them
- team chat
what you type
dont let senna get souls
in full english
Don't let Senna pick up her souls.
the context
Every soul picked up is permanent power. Zoning Senna away from dead minions, or punishing her when she steps up to collect, slows her scaling more surely than a kill.