Ooops, got the description wrong. They call it 'rolling-up' a plant.

I've been doing this for years but it works best with young plants that still have thin and flexible stems, and is a great solution for seedlings or cuttings that have grown crowded and/or become etiolated. In fact I don't see it being effective to control the mature height of a plant, mainly because the stems become too stiff and brittle--your best bet then is to simply repot the plant deeper.

One reason why it works is that most gesneriads can send out roots directly from a stem that contacts soil (as long as it hasn't become woody). Of course it will never be necessary if you don't let the plant get leggy in the first place!