behaviour

by play time stress!
(Northern Ireland)

Hi, I have a 1yr old male & a 6mth old female who get on great with each other. However, they seem to think "play time" is allowed all the time! How do I train them to be calm in each others company? It has got to the stage only 1 is allowed in the room at a time, then they get swapped over. When out walking on the lead they don't bother with each other until I let them off for a run about then they are up to their antics again! I have even taken the 6mth old to puppy training classes which helped with basic commands and interaction with other dogs, but hasn't helped at home. Any advice?