Striking
Although occasionally when my sifu demonstrates moves it hurts slightly, there is no real pain.
In Kung Fu Mag it said you must eat bitter to be a good martial artist, I agree with this to a point but surely your sifu should have more control? I could never stay at a class where the sifu was aggressive, it is the whole point behind kung fu - it was invented by peaceful monks as oposed to using it for killing such as in karate.
I think the main point really is whether you feel comfortable with it, if not maybe consider a different sifu?
Are you sure about this?