Please help! We have a 10 week old border terrier who is mostly loving and playful and an absolute joy. He can be very gentle and gives lots of kisses. But when we play, he nips fingers and toes, and it can really hurt! We have been using the ‘ow!’ method (stopping play and saying ‘ow’ loudly until he stops then resuming play - and if he doesn’t stop after 3 ‘ows’ we leave the room for 1 minute). However, after 5 days, the nipping isn’t becoming less frequent or less hard and I have noticed that just leaving the room isn’t doing much, as he just continues playing with his toys in the room alone. So my question is this - do you suggest a play pen to put him in without toys so he really understands that nipping = no play and attention for 60 seconds? Thank you in advance for you guidance!