My 5 year old DD is doing brilliantly at the moment. Her school have been wonderful, and she is relatively (for her) relaxed most of the time. Yet, this morning, she repeatedly scratched me hard enough to draw blood. Why? She needed a wee, but didn't want to go. This is a common occurrence for her - I think she gets overwhelmed by the extra sensation, and then freaks out. But we were running late, and we needed to drop her brother off first, so it would have been a long time until she could have had a wee, so she had to go before we left. She scratched me, because I (calmly) unbuckled her seat belt. Anyone else have wee wars? She can get really agitated when she needs to go, but if you suggest that that might be the problem, she gets extremely angry.
ds gets agitated and refuses to go so I always do a you go for a wee and then we'll be doing X. If we're out then there will be set times that always happen, like go for a wee before getting in the car so it's a fixed part of the routine.
If she needed to go before you left what was the unbuckling seatbelt about? I know if ds was already in position to do something he would not be able to handle things changing, for instance if you were already in the car and decided a wee needed to happen. So then it wouldn't be about the wee itself it would be about his whole expectations crumbling and uncertainty about everything.
She was already buckled in the car when she said she needed a wee. Then, when I went round to open her door, she backtracked and said she didn't. But she was wiggling all over the place, obviously desperate to go, and there would have been nowhere to stop before we got to school. I should definitely implement a wee before getting in the car policy - I normally do for longer journeys.