I had the same thing with Ardyn. I had to get strict, and nappy time wasn't a fun time anymore, it was something that needed to be done - not a choice. I never hit/smacked her, but was VERY stern and did need to pin her down at times. Yeah, yeah, I'm a mean mummy too. But you have to be sometimes.

It does get easier though. She's now at an age that I can reason with her to a certain degree, but she is only 2, and I still have to be stern at times.

My advice would be to get in and get out as quckly as possible, and show your them that you mean business and there's no other choice. This IS getting done whether you like it or not.

(Oh, but re reading what others have said, she did like it when I gave her the cream and let her squeeze it out a bit. I think that it made her feel like she was at least helping a bit.)