How to ride packed train as a woman

Hello, I moved to Japan recently and just had my first packed train experience. What should be done as a woman to minimise the uncomfortable experience of having your butt and breasts pressing against other people? Do you normally put your bag or hands in front of you to block? Just had my breasts pressed against some man's back for a second when the train shifted and I feel disgusting tbh. After that I kept a hand in front so I could hold his body back, but still. How do you do it every day?
Edit: actually cannot use the women's only train because the Chuo line doesnt have it in the direction I go when I ride.