Kakari geiko (stress training) is called "drill" in competition training, you can use it by lack of fitness, of both, TORI as well as of UKE (also falling is also exhausting). TORI executes an agreed throwing technique against a number of UKE, which move in rapid succession. This stress training may include a part of Yaku soku geiko where TORI and UKE appropriate roles are assigned. Incidentally, the decision power is trained because each partner behaves differently, it trains fast reactions of TORI.
Even as Uchi komi training with a single partner this type of training is possible, UKE stands up very quickly after he was thrown, to be thrown again. Kakari geiko can also be used as an excellent extension of the warm up training before a competition.