Instead of listing every hour of the week, begin with the commitments that shape your availability. "I have classes on Monday and Wednesday evenings, and I work late on Tuesday. Thursday is my best evening for the project."
Then identify a priority: "I need to finish the application before Friday, so I am keeping Thursday afternoon free." The listener can understand not only when you are busy but why one period is protected.
Separate fixed and flexible activities
Practice this distinction: "My appointment is fixed, but I can move the shopping." Both activities appear on your calendar, yet they do not limit your choices in the same way. Avoid describing everything as impossible to change unless that is actually true.
If you are discussing a shared task, offer a realistic block: "I can give it an hour on Thursday, but I cannot finish the whole presentation alone." Clear limits allow the group to distribute work rather than assuming your free evening means unlimited capacity.
Ask a partner to find a suitable meeting time using your spoken description. Then compare the proposed slot with your actual practice calendar. Did you omit a commitment or make a flexible item sound fixed? Revise the explanation and repeat. Planning language is useful when it supports a feasible choice, not when it merely demonstrates that you can name the days of the week.