Aside from managing the custom stay of your listings from the single listing calendar, another alternative to do this is from the Multicalendar.
Here are the steps to do so:
1. Open the Multicalendar
2. Click on the three dots at the right side of your Listing Nickname/Listing Title
3. Click on Min Stay
A sidebar should appear on the right side of the page, where you can adjust the following:
Custom minimum stay / Period Specific rules - from here you can select a certain date of the calendar or a period of the calendar (eg. the Christmas holidays).
Default minimum stay - this section will set the default minimum stay of the listing.
Weekday minimum stay / Checkin weekday rules - Under this section, you can specify a minimum stay only for a certain day of the week (eg. on every Friday, you want a minimum of 2 nights stays).
Sync children - If the option is marked, the custom stay rules will be auto applied to all of your child listings.
4. Click on Update to apply changes.