PSA: series commitment rings
The rings are linked to a smartphone over NFC, and the app connects to Netflix, Amazon, etc. You register the shows you want to watch together. Once you register, the NFC requires that both rings be present in order to watch the show.
The rings aren't for sale yet, so I'm not posting this in the deals forum. But those of you who are interested should sign up to be notified by email once the rings do go on sale.
I have no affiliation with this company.