I need some advices on bdsm things... :help: :help:

I am a young male master and I am interesting on knowing how to treat a maleslave.
I would like to know...how i can understand that he is ready to cum..in order not to let him!

I also want to know if there are some creams that i can have in order to keep him aroused.. [I need a creme that it is easy to buy..and something like counterpain(that I have heard)]. Please ,let me know the cremes and how to use them.

I also want to know...how I can understand then he is really to the edge of pain on his balls...
So sorry for my english level. I am waiting your opinion.
Thanks in advance.