To me the problem isn't the tool but the method. I use a prong and it's a great tool but it's never made Delgado shut down like the OP is describing, if it did I would quickly stop and think again about what I'm trying to get across.
Jasmine - Female Miniature Poodle - born Aug 15, 2010
Loker Delgado Von Stalworth - Male GSD - born Jan 26, 2012
Koda & Zazu - 5 year old male cats
Alex - Male Cocker Spaniel (rescue) - RIP Cuddlebug 2007-2010