.... I now practice at a dojo near my home in Denver. Sensei had me uke with a katatori. I was tired and did not know what move he was intending. When he did throw me, I forgot to let go of my katatori. While I was in motion, and without thinking, I executed a one handed hip throw (I studied judo when I was eleven). Both Sensei and I ended up on the matt looking somewhat stunned. I also tore his gi. He prefaced his next demonstration with, "and if Uke proves to be as obstinate as David can be, then you can do this..." and proceded to wipe the matt with me.
LOL! That was funny.
Reminds me of something similar but less dramatic. When I came back to Aikido three years ago, I was doing ikkyo (I think) and one of us stood up a little when he wasn't supposed to. (On refelction, I'm not sure it was me, although ti could have been, but then why did he work on my partner? Anyway,) Sensei saw it, came over and said -- friendly smile and all -- "If he stand up, you can do this....." and slammed my partner down with a sumi otoshi. (See? Now Im not sure whose mistake it was, but as a result of making that correction,) Sensei was very pleased -- my mistake had inspired him! When he demonstrated the technique, the woman next to me said, "My husband is expecting me home alive." Fortunately, all of us new people could use a basic sitfall to take ukemi.
Fast forward to a few months ago. I don't remember exactly what technique it was, but when Sensei came over to correct us, and he spun away so forcefully I could not hang onto him! I don't have the strongest grip in the world to start with, and he spun out of it. "And if he lets go," he said, "you can do something else." Next thing I knew his hand was in my face and the tatami was greeting my backside. Again.