Hard nipple sucking/preterm labor help

Earlier my husband was sucking my boobs pretty hard. I took a nap, and now my back is hurting really bad but just in one spot. I’m 27 weeks but with our last kid 3+ years ago I remember going into labor after a round of sex and nipple sucking. I’m worried because the spot that is causing pain was literally the same spot where my contractions started 3+ years ago. What kind of nipple sucking is okay to make me not go into labor??? And did I just push myself into labor??? Is it even possible to do so??? My last two kids came at 41+ weeks and 38 weeks. Help.