Well, I've only had one baby. He nursed twice during the night (roughly 1 am and 4-5 am) until 6-8 months at least.
We switched to bottle for some feedings, including the 1 am, and gradually reduced the volume of milk for that feeding until he stopped waking up at about 1 ounce.
But I wouldn't do that for a 4 month old, he's too young and he may geniunely need to be fed (DS was much older and eating soldis, too). Our Ped said it was totally normal for EBF babies to nurse 1-2 times per night until around 6 months, and that they do actually need it, but after that it's OK to do some sleep training.
We had a 6 hour stretch at about 2 months, but that lasted less than a month. Then it appeared again a couple of months later, but it was 7 pm to 1 am, and then he was back on nursing every 2-3 hours
I highly recommend reading Dr. Ferber's book (Solving your child's sleep problems, the latest edition since it's been thoroughly revised) to understand sleep cycles and what's actually a problem. He talks about many different causes and gives several solutions (the gradual CIO is the most popular, but not the only one).
Other than that all I did was go to bed earlier and at least a few times a week I'd nap along with him during his long nap of the day. And I adjusted my expectations, everyone IRL says their babies STTN at 2 months, but I doubt it's true in most cases from what I've seen with other moms in our playgroups.