Might need more context, sounds like 'one and ones' could be specific terminology.

Could they possibly have said "one on ones." In my industry, that means a regular meeting between two people (usually a supervisor and a worker) where they talk about how things are going. The supervisor can let the worker know if they're doing well, or if they need to improve in one or more areas (e.g., "you're great at designing." "you need to work a little more on planning.") The worker can let the supervisor know if there's anything they need (e.g., "There's a class I'd like to take." "I have too little work, I can take on another project."). It is something that managers have to learn to do - otherwise the meetings just do not work.

I have never heard it, sorry.

Agreed. The specific phrase you are asking about does not make any sense.

It makes no sense