After 3 more classes, Here's a little personal update on the "getting hit for real part"
As I said, the mental preparation for that seems to be THE main thing.
Even if it hurts a little (mostly your feelings), if you go in there "prepared" for the fact that you will get punched, You tend to increase slightly you defense level and learn a lot faster.
If the guy in front of you isn't too stupid, just tell him to soften up a bit. otherwise, don't hesitate to increase the power of YOUR punches to make him understand