to teach them the closed tunnel. the closed tunnel is a little more challenging than the open tunnel, but if your guinea pig has already learned the open tunnel and can do it well, they should be able to pick up on the closed tunnel quickly as well.
hold the collapsed part of the tunnel open with one hand. with the other, lure the guinea pig through and reward. practice a few times until the guinea pig can go through without a lure.
gradually hold the collapsed end slightly lower each time.
after awhile, try leaving the collapsed end on the floor and see if the guinea pig will come through it. if 