So DS (2.8) had started to be really interested in the potty, asked to sit on it several times a day, seemed excited when presented with the option of pants etc, but if he's ever naked or in pants he's fine until he needs a wee and then suddenly starts hopping around holding his willy getting really distressed and saying he needs a nappy on. If I try to reassure him or offer him the option of the potty/toilet he gets more upset. Eventually I got out of him that if he wees on the potty, he thinks I will be cross. I don't know why he thinks this except that he has had a few accidents on the floor when naked and although I used to be really blase about this and just say matter of factly "oh look, you're doing a wee wee on the floor", more recently I tend to automatically shriek "Stop stop!" and look around ineffectually for a potty to catch it in, which I know I shouldn't but I don't even realise I'm doing it :( I have always been really reassuring afterwards and "Never mind, look, we can just clean it up with this cloth, you did a wee wee! That's really clever!" etc etc.
I've tried telling him that I won't be cross, telling him that I would be happy, telling him I would be proud, even offering the idea of chocolate buttons, but he doesn't seem to understand or believe me (not sure which) and I have a horrible feeling we're past the stage now where I can just let him wander around naked and be prepared to react to accidents in a very neutral way because he just hates being naked so much now.
I'm starting to get a bit nervous about it though as I was hoping he would be able to start preschool in January (possibly even October) but they won't accept children who aren't potty trained.