Male cat is being sexually aggressive with smaller female cat, is there anything we can do?

We have ~3F, ~2F, and ~1.5M. All of our cats are spayed/neutered. They all get along really well but sometimes the male cat displays mating behavior towards our younger female cat that she does not reciprocate and is very distressing towards her. Our male cat is bigger boned and 2F is tiny compared to both of our other cats so it’s difficult for her to get away from him when he acts like that.

Is there any way to train him out of it? I know it’s a bit late to start but this has started over the last few months and has been getting concerningly frequent. We have feliway mist going and use calming treats as needed but it still happens. We separate them if it does happen. He never does this with 3F.