males in training?

[Murph's Mom]

I saw the messages concerning raising puppies of the same sex and age together and I have a question. I have my puppy in training and he is in the same class as our neighbour's puppy who is the same sex, breed and 2 wks older than mine. They have spent considerable time playing together in both my house and my neighbour's since they were frst brought home. My problem is that we have horrible trouble keeping them focused, as well as the fact that my puppy seems to become more aggressive as class goes on and then after class. Is this normal behaviour?