During an instructional flight in the glider, the student pilot reported that, he turned onto final approach early as he felt that he was low. The student lined up with the airstrip and reported that the touchdown was not smooth, and the glider was angled slightly to the right. The glider bounded and turned more to the right. Before he could make a correction, the glider veered off the right side of the airstrip and collided with terrain. The flight instructor reported that, he should have been more proactive when the student delayed in turning to the base leg due to his confusion with the runway appearance as he thought that the student could handle things himself. The glider’s empennage was substantially damaged. Neither pilot reported that there were any preaccident mechanical failures or malfunctions with the glider that would have precluded normal operation.