stimulating Nipples

Leah • Pregnant w| my 3rd baby 2nd girl & this pregnancy. Been treating me right EXCEPT THE TENDER BOOBS 😩🤦🏾‍♀️ ✨
Has anyone stimulated their nipples and it started labour when I stimulate mines it does bring on contractions (strong ones)  I'm really just wondering how long do I stimulate my nipples before labour actually starts ? Please comment