How can i decrease my milk supply?

Slowly: If possible, it is best to decrease your milk supply slowly over a couple of weeks. Start by going longer between feeds (or pumpings) and just pump or feed enough to relieve pressure, but not enough to fully empty the breast. You can do this at certain times of day if you just want to eliminate certain feedings.

Decrease feedings: Your body will adjust the amount of milk it produces depending on how much it perceives your baby needs. (that is why some mom's can successfully nurse twins.) that being said, if you cut down on the number of breastfeeding sessions (and offer either expressed breastmilk or formula), your body will over time cut back on the amount of milk it produces. Do this gradually to avoid engorgement.