I have heard claims from erotic fem dom hypnotists that they can achieve erection on command with some work. As stated, it is basically a pavlovian response but (and here is the difference) it is possible to consciously resist it (dogs don't bother to resist the stimulus, humans sometimes do but not as often as we'd like to think we can).

They work by linking something that already makes you aroused to something else - a keyword - and then repeatedly associating the two until the keyword works alone.
I have yet to see evidence of this, however. Also, this is erection not ejaculation or orgasm.

I think one important step is to 'get to know' the penis in question and the man attached to it. What works for one does not work for all. A lot of that is trial and error. Jennifer stated above that she only has to say a few words to get him started and that shows that she knows her guy well enough to know what to say and how. Thats a combination of his training and her learning...

Men are, of course, already well conditioned to respond to certain stimuli. The sight of breasts, underwear etc usually get a response and to a submissive male, any strong female is likely to find it easy to get a response.