Q&A: How Do I Treat An Overactive Letdown?
Basically, this means you're making a lot of milk, and when it starts coming out, it comes out hard and fast.
To tame an overactive letdown, you'll need to help your body make a little less milk. Do this by nursing on only one breast per feeding for a while, or even one breast per block of four hours. (For example, only the left breast from 8 a.m. to 12 p.m.; only the right breast from 12 p.m. to 4 p.m.) If the other breast gets crazy full, express just enough milk to feel relief.