I need help

My bf is Trans, I'm not, he has really large breasts and he keeps suggesting he wear a binder during intercourse, I keep telling him that it's unsafe, it's really dysphoric to him for him to wear a bra of any kind during sex, I just want him to feel comfortable, is there any safe alternatives for him to use other than a binder? He can't use trans tape his man boobs are too big, I just need a safe alternative to him binding, I don't want to see him get hurt