I had tt too. Try wearing breast pads. Was told not to express till about 36th wk. Aft tt, some moms express occasionally into syringes and freeze it for use upon birth. I regretted not doing it as I had supply issues in my first wk when baby was in NICU for jaundice.
You'll leak when you're pregnant and it's really common. It's your colostrum. The 1st milk that will come out. Nothing to worry about actually and yes, do not try to express cos it will trigger contractions.