What appears to be a simple latex bag is not what it appears. It is in fact an air tight sack with a hole for one's head to stick out. A few friends play around with this, inflating and deflating the sack with each other inside. Both are equally inescapable, but the inflated version is much roomier than the deflated version, which leaves the person inside unable to move their limbs. This was good to know when Hinako entered the sack and was deflated, leaving her in a position to get her pussy stimulated by the Hitachi. Don't be fooled by her screams of terror. She enjoyed it.