The swag is sausage-shaped bedroll of several layers. The outside layer is a tent or a strip of canvas. It covers the swag and is used as a shelter in bad weather. In former days two blankets were used, usually blue. Inside the bedroll one would put his spare clothing, towel, soap and personal belongings. When it was time to camp, they would unbuckle and unroll it as easily as a roll of wallpaper. The swag was ready on the ground with the spare clothes for a pillow.
Nowadays the swag has a thin mattress inside and either a blanket or sleeping bag. The swag is used to sit on while around a campfire. Only unroll the swag just before going to sleep as some wildlife creatures might be crawling into it giving you an unpleasant surprise while sleeping.