how to avoid accidents during sex?

I’m having my first experiences with my boyfriend and I’m having several problems involving body awareness, especially with my thighs

During the first time I sat on his face, he asked me to put my full weight on him, but I ended up suffocating him with my thighs. Something similar happened when I sat on his Adam’s apple

In addition to suffocating him a few times, I ended up having several problems with pain from being “too tight”

While we’re having sex, I make several mistakes because I’m too engaged, so I don’t realize what I’m doing and I end up hurting him or causing damage to my private parts.

I understand that for some people these body characteristics are very desired, but I have a lot of insecurity about them and I’m afraid of ending up causing bigger problems because of them.

Any tips on how to make sex safer and more enjoyable?