Abstract: The present invention is directed to a bagging device for directing a flowable substance from a transport trailer to a flexible agricultural bag. The device includes a tunnel housing attached to the back of the trailer. The open end of the bag is held behind a ridge member and between the ridge member and a stretchable strap so as to resist release of bag until the bag on the ground has been filled. A tray beneath the housing supports the bottom portion of the bag to prevent it from stretching and ripping. A shield near the tires of the trailer prevent the bag from entangling in the tires. The device is especially appropriate for use with flowable commodities such as brewers grains and stillage by-product which rapidly deteriorate unless promptly stored in an air exchange-free enclosure.