Rear-facing Tether (Britax, Diono/Sunshine Kids Radian, Peg Perego 5-70, Combi Coccoro)
This video, courtesy of Britax, shows how to secure the rear-facing tether. It first shows how to use the tether connector strap to create a rear-facing tether anchor – and then demonstrates how to connect your child’s car seat’s tether strap to the tether connector strap. The tether connector strap typically gets wrapped around the seat TRACK of the front seat. Most seat tracks have a cosmetic plastic casing on them, that gets in the way of wrapping the tether connector strap. In most cases you can easily (well, you might have to pull pretty hard, but it is definitely doable) remove the plastic casing (they did in the video below) and you will get a much better fit with the tether connector strap. When the tether connector strap is removed (i.e. when the child goes forward-facing) you can then snap the plastic casing back on.
Note: The video shows two ways of tethering – Australian & Swedish style. Britax seats allow for either method to be used. The Peg Perego Primo Viaggio SIP 5-70, Combi Coccoro and all versions of the Sunshine Kids / Diono Radians ONLY allow for the Swedish method.
If you have a Combi Coccoro, you can get a rear-facing tether kit (i.e. a tether connector strap) by contacting their customer service department at email@example.com or calling 1-800-992-6624. Rear-facing tethering is not discussed in the Coccoro manual (it will appear in the manuals starting soon), but in 2011 Combi retroactively allowed rear-facing tethering on ALL Combi Coccoros (regardless of whether it is a new or older one).
If you have a Britax seat and lost your tether connector strap, you can order one from Britax ($5) (plus shipping).
If you have a Peg Perego and it did not come with the tether connector strap, you can call the company and order one.