One way of blocking your room is seen here
You can also use the 'Maximum availability' feature in your OTA Dashboard to easily adjust your room availability for each OTA.
Why is this helpful?
1. You can quickly set your availability to zero if you want to block off that room type on a specific OTA.
2. Have you ever seen this notification on an OTA?
You can use this tool as a marketing technique by advertising that you have only a few rooms left.
Also in case you work with allotments among OTAs, Travel Agencies, B2B suppliers, etc, you can select different quantity of rooms available to each player.