this is probably TMI...but if you and your man do it often and he already touches your nipples it probably won't work...like it would work for me because my husband is constantly on my boobs but just like @deafmama16 said sex works and also walking

Didn't work for me but squatting and sex plus regular herbal raspberry tea put me in labor the next day golly gosh

it doesn't work and no it doesn't hurt. I do it and did it before I was pregnant. it's a habit since my nipples are sensitive.