These bottle usually have one pin thin hole in the nipple. (expressing-mama.com)
The suckling will draw out the milk through tiny holes in the nipple shield. (lovingmomentsbras.com)
Since there are approximately 15 to 25 milk ducts in each breast that make milk, there are several pores in each breast where milk comes out of, not just the single hole in your nipple. (lactationconsultantresources.com)