Sex to induce labor or orgasm?

As some of you know, sec is difficult in the final weeks! My husband and I end up laughing and problem solving through most of it. I want to use sex to help induce labor, but it is just too uncomfortable. So is it the sex, or just orgasms that help labor along? I know semen softens the cervix (according to my doctor mine is 'mushy' 🙄). But I think oxytocin is released with orgasms and that is what induces, right?