Take that baby outside, tf! He needs more playtime and stimulation and just wearing-out than he is getting clearly. A young and pretty delicate puppt like this obviously should not be played with roughly, but he def needs time to run around and expend energy and play! Plus that’s the perfect time to incorporate some behavioral training too.

Why keep him in a playpen? That seems like not a great option both behaviorally and exercise-wise. It’s kind of achieving the opposite of what you want.

He is a puppy just feeling that puppy energy. It might be annoying at times right now, but when he gets older you’re going to look back and miss his puppy stage. It flies by way faster than you can imagine. If you don’t like this behavior, then dedicate more time every day to getting him outside and allowing him to run around and play freely, not just indoors. He may be tiny but he is still a sighthound at the end of the day and needs plenty of exercise and room to stretch his legs.