How To Fix A Slacker Boob

You finish a pumping session, look at your bottles, and—ugh. One side is overflowing with milk while the other barely covers the bottom. Say hello to the slacker boob.

I know this frustration all too well. When I went back to work as a first-time mom, I’d sneak away to pump during breaks, only to discover one breast pulling its weight while the other slacked off. I remember sitting in my office with mismatched bottles, wondering if I was doing something wrong.

Here’s the good news: you’re not broken, and you’re definitely not alone with a lazy boob. Slacker boobs are a super common part of breastfeeding and pumping. In fact, most moms notice some uneven supply. The key is understanding why it happens and what you can actually do to fix it.

In this post, we’ll cover:

What a slacker boob really is (and why it’s so common)
Signs that one side is underperforming
The most effective ways to increase supply on your “lazy” breast
Practical tips I’ve personally used to get my slacker side back on track

Let’s get your boobs working together again.

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Table of Contents

What is a Slacker Boob?

A slacker boob, or lazy boob, is where one breast produces less milk than the other. It is completely normal to have a slight variation in milk production.

A slacker boob (also called a lazy boob) is when one breast consistently produces less milk than the other. And yes, it’s as annoying as it sounds. While it’s totally normal for there to be slight differences, sometimes the gap is big enough to notice — like when one pump bottle fills up fast and the other one barely gets going.

2 breast pump bottles with uneven amount of breast milk showing a slacker boob

When I first started pumping at work, I thought I was doing something wrong because one side always lagged behind. But the truth is, it happens to so many of us. In fact, when I surveyed 100 moms, 88% said they had a slacker boob. And funny enough, more than half (58%) said it was their right side that fell short.

According to La Leche League, it’s very common for one breast to make more milk than the other, and most moms notice some uneven supply.

So if you’ve got an “overachiever” breast and a “slacker” breast, you’re not alone — you’re actually in the majority. It doesn’t mean your supply is doomed, and it definitely doesn’t mean you’re failing. It just means one side needs a little extra encouragement to keep up.

From a survey of 100 moms, 88% of us have a slacker boob. And of those, 58% had theirs on the right side.

*Note: this survey was performed on social media and may be biased towards moms with slacker boobs who are more likely to respond.

How to Tell if You Have a Slacker Boob

Not sure if one of your boobs is underperforming? Here are some telltale signs that point to a lazy boob:

Your baby prefers one breast. If you’re nursing, your little one might fuss, pull off, or flat-out refuse one side. Babies know where the good flow is, and they’re quick to turn their noses up at the “slow” tap.
One bottle fills up faster. Pumping moms notice this the most — one bottle fills steadily while the other looks sad in comparison. (This was me in my office pump breaks. I’d hold up my bottles and sigh because one always looked half-empty.)
Your breasts look uneven. Over time, the overachiever breast can become physically larger than the slacker, especially if the supply difference is big.

If you nodded along to any of these, chances are you’ve got a slacker boob. But don’t panic — it’s common, it’s fixable, and the next step is figuring out why it happens.

image showing asymmetrical breasts for slacker boob

Why does a Slacker Boob Happen?

Breast milk production runs on a simple rule: supply and demand. The more often milk is removed, the more your body makes. If one side isn’t being emptied as often — or as effectively — it naturally produces less.

There are a few reasons this can happen:

Baby’s preferences. Sometimes babies are picky. Maybe your little one gets a faster letdown from one side, or latches more comfortably there. Over time, that preferred side gets more demand — and more supply.
Nursing habits. If you tend to start feeds on the same breast every time (guilty 🙋🏻‍♀️), that side will get more stimulation and outproduce the other.
Physical differences. Most women have slight anatomical differences between breasts. Maybe one has more milk ducts or better drainage. It’s normal, but it can make one side “work harder” than the other.

mom pumping one breast for slacker boob with sleeping baby in the background

When I was back at work and pumping, I realized I always set up my pump on the same side first — and sometimes even forgot to switch during middle-of-the-night feeds. Looking back, it made perfect sense why one breast became the overachiever and the other turned into the slacker.

The good news? Because it’s usually just a matter of supply and demand, you can often train your slacker boob to catch up. And that’s where the next section comes in.

The key to fixing a slacker boob is simple: increase demand. The more stimulation that side gets, the more milk your body will make. Here are some tried-and-true ways to give your slacker a boost.

baby nursing with mom looking down for slacker boob

Pump for Extra Credit

After your regular pumping session, keep the slacker boob going for an extra 5–10 minutes. You may not always see more milk come out right away, but the nipple stimulation signals your body that more is needed.

When I was pumping at work, I started setting a timer to make sure I gave my lazy side extra attention. After a week or so, I noticed it wasn’t quite so far behind my overachiever.

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Power Pump the Slacker Side

Power pumping mimics a baby’s cluster feeding, which tells your body: make more milk, now! To do this, pump just your slacker side in intervals (20 minutes on, 10 minutes off, repeat for an hour).

I saved this for nighttime after my baby was asleep so it wouldn’t interfere with regular feeds. It was tiring, but after about 5–7 days, I started seeing better output.

Infographic titled "Power Pumping: How to power pump in 1 hour to increase your breastmilk production" showing a cycle of pumping for 20 min, resting 10 min, pumping 10 min, resting 10 min, and pumping 10 min.

Use Heat

Applying warmth before or during pumping helps open up your milk ducts and makes letdowns easier. You can use a heating pad, warm compress, or specially designed breast therapy packs.

Personally, I kept a microwavable heat pack in my pumping bag at work. It made those sessions more comfortable — and my slacker side responded with a little more flow.

woman single pumping breast for slacker boob

Add Vibration or Massage

Massaging or vibrating the breast can help milk flow more freely and prevent clogged ducts. Lactation massagers are great, but you can also use something as simple as the back of an electric toothbrush.

I remember trying this during a late-night pump session and being surprised at how much milk I got after a few minutes of gentle pressure. It doesn’t feel glamorous, but it works.

Nurse From the Slacker Side First

If you’re breastfeeding, start feeds on the slacker side. Babies usually suck strongest when they’re hungriest, so putting them on the underperforming breast first increases stimulation and demand.

When I started doing this, my baby fussed a little at first — but over time, she got used to it, and that extra stimulation helped balance my supply.

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Slacker Boob FAQ

Is it normal for one breast to produce more milk than the other?

Yes — it’s completely normal for one breast to make more milk. Many moms have an uneven milk supply, often with one “overachiever” side and one slacker boob.

Can a slacker boob catch up?

Usually, yes. By using techniques like power pumping, extra pumping sessions, or starting feeds on the slacker side, you can encourage your body to increase supply. Results vary, but many moms see improvement within 1–2 weeks.

Which breast is more likely to be the slacker?

From a survey I ran with 100 moms, about 58% said their right side produced less milk. Still, it can happen on either side. What matters most is consistency in nursing or pumping to help balance your supply.

Will a slacker boob affect my baby?

Most of the time, no. Babies are excellent at getting what they need, especially if you offer both breasts during feeds. If you notice your baby refusing one side, it may just be because of the slower letdown or lower supply.

Can I prevent a slacker boob?

You can’t always prevent it, but you can lower the chances of one side falling behind. Switching up which breast you start nursing on, making sure your baby has a solid latch on both sides, and paying attention to breast massage and heat during pumping all help keep supply balanced. If you’re pumping at work or away from your baby, try to give equal time to both breasts so your body doesn’t accidentally create an uneven milk supply.

Infographic of 5 solutions to fix a slacker boob

Finding Balance with Your Slacker Boob

Dealing with a slacker boob can feel discouraging, but remember — it’s one of the most common challenges for breastfeeding and pumping moms. With a little extra effort and consistency, you can usually bring that side up to speed.

What worked for me was a mix of extra pumping sessions, warmth, and starting feeds on my lazy side. It wasn’t an overnight fix, but within a couple of weeks, my supply evened out enough that I didn’t feel lopsided anymore.

If you’re in the thick of it right now, know that you’re not alone — and your body is not failing you. Try a few of these strategies, give yourself grace, and celebrate the wins (even if it’s just an extra ounce from your slacker side).

💬 I’d love to hear from you: Have you dealt with a slacker boob? Which of these tips do you want to try first? Share your experience in the comments — your story might help another mom who’s struggling, too.