Well it depends on your goal. Different women use the strap-on for different reasons, and with different objectives in mind. For some, it’s just another form of sexual play. For others, it’s a means of exercising her dominance and authority over him.
Certainly, if your goal is to totally emasculate him and render his penis worthless, frequent use of the strap-on, coupled with extended chastity can have the effect of essentially re-wiring the pleasure centers in his brain. By stimulating his prostate via strap-on fucking, while denying him any direct stimulation of his penis, he will, over time, begin to associate his own sexual pleasure with anal penetration. You will notice that he’ll start to leak semen, while his penis is soft, in drips and dribbles, while you fuck him. He’s not having an orgasm; his prostate is being milked. It is both intensely frustrating and curiously pleasurable for him at the same time. Frustrating because it feels to him like he’s always on the verge or edge of cumming, but it never happens. Pleasurable because of the excitable nerve endings on his prostate. Then what you want to do, about once every twenty days, is release him from chastity, proceed to fuck him the strap-on, grab hold of the base of penis (it will be nice and hard for you), but do not touch the sensitive head, and give him a good hard fucking. Then when you’re ready, just barely touch the head of his penis with your fingers, like you’re strumming a guitar, and he will blast off like a rocket. You want him to cum like that while you’re still all up in his ass. After his penis goes soft (and if it’s taking too long, use ice), immediately lock him back up. He needs to feel that immediate authority from you.
Keep this up and he will, over time, go from resisting the strap-on, to tolerating it, to enjoying it, to craving it. But only if you keep his penis locked up 24/7 and don’t otherwise allow him to cum. If you have the patience and determination to maintain the discipline, you will see how effective it is. After a while, he’ll start putting his ass up for you frequently and spontaneously, like a bitch in heat, because he needs and wants that stimulation.
You can effectively cause the same physical/psychological conditioning regarding him sucking cock, if you want to. It’s a little more complicated, but can be just as effective. I’m currently in the process of doing exactly this with my hubby. By the end of the summer, my goal is to get him to the point where he associates sucking cock with his own orgasmic relief.