Prostate Massage during sex: choose orgasm or ebb n flow?

Hi,

what are your experiences with having the Aneros in during sex with a partner? I hear that the prostate being massaged causes erections, and from others, I hear that it is hard to concentrate on erecting... so how does one get to being able to have a FULL penile/perineum/prostate sexual experience?

I want the Aneros to be both a solo and partnered thing, so I want erections during its use.

A big question is:

If you have it in during sex, can you CHOOSE the type of orgasm you have - penile or prostate? For a prostate orgasm, do you have to sometimes "ebb and flow" (stop thrusting) so as to make sure you don't have the penile/ejac orgasm? Can you tell which is about to come first? Can you CHOOSE wave after wave of p-orgs then switch to a penile-org to end with (if required)? If you accidently have the penile/ejac-orgasm, I guess you are in the refractory zone, right?