He's still a little guy and needs to know the proper way to behave with your family
He's doing what all puppies do and that's play
When two puppies play and one goes overboard the other will yelp
That's a sign for the other one ... that's too much
and usually they will stop
When he does this you need to Yell .... NO! or OW! or NO BITE!
something that will stop him in his tracks
Then if you're sitting on the couch...... off he goes
If you're sitting on the floor .... you get up
If he's biting your toes you walk away
But where ever he is he is left alone ... all interaction stops
and you'll be surprised how quick this guy will get the message
Dogs and esp puppies Live for your attention
and if you take it away they will find a way to get it back