*Disclaimer*
I have not eaten durian. The "custard-on-the-toilet" phrase was used (independently) by two people I know who have.
I also know durian is banned from many hotels and forms of public transport in S.E. Asia.
ETA: Of course, if you want a really good durian, you want one that's already been eaten and shat out by an elephant.
http://www.soshiok.com/article/13783