When is stimulation of nipples end to prevent labor?

Okay this might sound completely crazy but this pregnancy I am soooooo horny, me and my fiancé have a great sex life but I also love to pleasure myself too. I'm 25weeks pregnant and I canbonestly climax will just massaging my nipples that's all it takes right now. Butttttt I'm also afraid of starting labor, I have heard to start labor towards the end massage and stimulate nipples but then if that's the case should I stoppppppp this now bcuz I don't want to trigger early labor at alllllllllll. I need advice please, have any of you ladies continued pleasuring yourselves, or should I stop . Any advice would be so welcomed.