An instant lesson is a 15- or 30-minute lesson a learner can request from you here and now. You can set the price for instant lessons by going to "Tutor studio" > "Private lessons settings".
Here, you can also choose not to receive instant lesson requests by keeping the "Allow requests for instant lessons" toggle switch off.

If you don't want to receive instant lesson requests during your livestream:
1. Under the player window, find the block called "Private lessons during stream"
2. Keep the "Allow requests for instant lessons" toggle switch off