[nycyorkiemom]

Using the playpen when you have had enough is perfectly fine if you put him in there unemotionally and make him feel that all is well. He won't know it's a punishment unless you do it angrilly. So don't feel bad about putting him in there if you feel you've had enough. It can be used as a break for you, and he'll just be thinking "okay now I play in here" and won't make the association that playpen/crate=bad. In fact the book "idiot's guide to positive dog training" recommends doing this to avoid losing our temper, and advises to treat him when in the crate/playpen to assure the dog that it is not punishment.