A different kind of yoga class - but it wasn't agreed that way

I have been practising yoga regularly again for some time now. To make sure I do the exercises correctly, I've hired a yoga teacher who comes round once a week for a yoga class and shows me the correct postures. But this time it somehow got out of hand... I was just about to do the morning one, but while correcting me he touched me in places where I am very sensitive. Suddenly he pulls my trousers down and gives me a different kind of coaching on the position..,