You can encourage guests to book longer reservations by creating a discount in Wheelhouse.

Select the specific listing you'd like to set a long term discount.
On the Settings page, click on Long-Term Discounts on the left panel.
Enter in the percentage for Weekly and/or Monthly Discount and select Save & Sync.
When a guest makes a long-term discount, this is what they should see on Airbnb (and other channels):

Note
If a guest books for a month long reservation, the weekly will not apply on top of the monthly discount. Only the monthly discount will apply.
Wheelhouse does not override Long Term Discount Settings for Hostaway, Hostfully, MyVR, Smoobu, Streamline, Tokeet and Tripadvisor.