The way I've heard it should be done is to use a hair net and stretch it over the bowl with the seat down and sprinkle litter on it. It has to be a kitten in order to learn this technique. After a while when the kitten uses it regularly remove the hair net. The hair net teaches the kitten to balnce themsleves on the edge of the seat, I don't see where setting the litter box on the seat would do that though.

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dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles