I'm surprised by the comments that this uke seems to be making. How old is he?
As far as doing your own techniques go, I would say to go ahead and do them. Ukemi is for the uke's self protection. If he doesn't want to tap, than that's his problem. (note, this doesn't mean snap his wrist. Slowly, carefully, and with a lot of control, put in the lock until he taps. [this is also good training for his wrists, so you aren't doing anything bad or immoral