She didn't object the first time because she was being polite and didn't want you to think she was kink shaming you.
The funny thing is, without going into too much detail, we enjoy doing things that these videos heavily feature. The upside-down head position, schoolgirl act, name calling, slapping, etc. From what I gather, with the movies it's not what's being done that bothers her,
but how Max does it that gives her the creeps, if any of that makes sense.