This is what we did the first few years I went climbing – you made several loops around your waist, tied a bowline and started climbing. When you fell, you usually wanted to get down quickly – not hang on a route and have multiple takes.
(I have noticed older climbers belaying using their brake hand in a palm up fashion, instead of the more common and safer palm down fashion. Because we always did a body belay – put the rope around the belayer’s back – you would naturally use the palm up position to brake the rope around the belly of the belayer. Easy to show, harder to describe.)
Anyway, there are a lot of old school ways of to make emergency harnesses in this article. Including this diaper sling which we used as an upgrade to the rope around the waist shown above.