The first few times with DS2 I actually sat him there with a book whilst my Dad was on the loo... and had Dad read to him! He actually had a nappy on, but it was more about getting him used to it.

THen we played a game of "upsies and downsies" to get him used to the physical aspect of sitting down on the potty and getting up off the potty. It was lots of fun.

Finally we ended up taking the nappy off and sitting down to read a book...

Otherwise perhaps a "special seat" rather than "potty"???