
As suggested, with some puppies, yelping only brings them back for more "yipee, I'm getting a reaction". If you watch siblings in the nest, when one attacks another, the one being attacked will probably yelp but also TURN AWAY. It's the turning away that matters ....... and in humans, that is best copied by ending the contact. Apart from trying not to get the puppy quite so worked up/excited (hard

), if this happens, end the playingm, stand up, say No Biting! so hopefully the puppy understands about unwanted behaviour, take the puppy out to empty and back to where he sleeps. Leave him to settle down for a nap - and you really should be using a crate so there's no possibility of him chasing you and nipping from behind. As puppies sleep lots, after some complaining he should settle down for a nap.
Puppies need to learn there will be consequences for actions, good or bad.
Just one concern about what's going on, which is pretty normal for puppies, this is a Cocker and
some Cockers (usually solid tans) have what's called Cocker Rage. Breeders are aware of this, and should be making sure they stay away from lines that do have this problem. Hopefully this isn't what this is about!!