I finally broke down and bought one of the Snoozer lookout console carseats...we normally just put Mojo's basket there w/ his blanket, but it would move and slide around and he could move around. Well, the console lookout has been GREAT! It attches (easily) under the two front seats and then a strap around the console lid. If you need to take it out, you just snap the straps off at the buckles (so you don't have to get under the seats again, that strap stays there). Mojo LOVES it! It has an adjustable strap w/ a clasp on it to attach to their D-ring on the clothing or harness - you can adjust it where their movement is just where you think it should be.
This may not be an option for you, but I just didn't want something that would take up a seat and something way back in the backseat (ha).
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