Cluster feeding usually happens during the first 3 to 4 months. It's when your baby wants to feed even more frequently (sometimes constantly) over a period of time.
It's very normal and nothing to be concerned about. Your baby may want to cluster feed during the day or night (or a bit of both). Your baby may cluster feed for a few days when they are going through a growth spurt.
You can cluster feed formula milk, but it's important not to overfeed your baby.
Watch your baby and follow the cues for when they need a break – these signs will be different from one baby to the next. They may splay their fingers and toes, spill milk out of their mouth, stop sucking, turn their head away or push the bottle away.
You should be able to tell when they're full as they will not want the bottle any more or may just fall asleep at the end of the feed.