Reference: "Ami Uchi," see Sam Combes, Aiki-do, Volume 5, Black Belt Video, 1999.
Also, "Kaiten Nage," page 250-255 of A. Westbrook and O. Ratti, Aikido and the Dynamic Sphere: An Illustrated Introduction, Tuttle, 1970.
Step 37 is the final move of Empi kata. We just landed after the jump, and we are in a right knife-hand-block kamae. In step 37 we take a step backward in back stance, and do a left knife-hand block. All versions of the kata except isshinryu's end with the same two knife-hand blocks.
The best we can do here is to reprise the lesson on "ami uchi" (kaigen nage) from the final cluster of Heian Shodan. We strike the vagus nerve with the right knife-hand while capturing his right wrist with our left hand. Then, as we step back, we lever his arm up behind him and push his head down. He does a forward roll. The throw is actually executed during the "stackup" for the second knife-hand strike.