This new bidding option is available to anyone from the collection profile page on Rarible web. The button lives right below the description and it will open a pop up where you can set your bid. This offer will be available to all owners of NFTs from this collection.
ICYM: Apart from this, don't forget to check the collection stats that are available in the standalone tab. This view can show floor price change and loads of other stats. This feature still has a "New" label next to it.
Source: Rarible on Twitter