Rocking blankets are a bit of genius, really. We used to do this up at the cottage in the summer - load someone in a large beach towel and then swing them back and forth, but without the convenient handles, which make all the difference, unless your intended end-result was a child catapult.
With handles, this is a much less dangerous affair! Rocking blankets are 80% wool, 20% acrylic, and feature comfortable strap-handles for peaceful rocking. €39.95. Rock someone's world!