An example airbag assembly includes an airbag and a duct. The duct has a duct opening for venting gas. The duct is moveable between a first position where the duct opening is outside the airbag and a second position where the duct opening is inside the airbag. Inflating the airbag moves the duct between the first position and the second position. The airbag is configured to be inflated by a first stream of gas moving from the duct opening to an interior of the airbag and by a second stream of gas moving from an airbag inflator to the interior of the airbag. The first stream of gas is separate from the second stream of gas.