We are a 2nd time dog owner. Our first dog Sneakers was a female mini schnauzer who passed away this past February at the age of 13. We recently got a male schnauzer/pomeranian mix Oreo who is almost 5 months. he loves to play (as most puppies do) but we find with female people, he plays hard and jumps and nips mores than he does with male people. He has not yet been castrated. Any thoughts on what this is and how to deal with this? Many thanks.