Slightly off the gag topic, but I've found that having my sub visit the porn/fetish shops with me is a nice humiliation for her. I make her ask for specific items at the counter and have the clerk show her what she is looking for, then have her pay for the items. She, of course, has to wear appropriate slut attire for these field trips. It's fun to watch the looks she gets from the "browsers". For me, e-bay would take half the fun out of it!