Sounds like Bits by Naomi Kritzer, originally published in the October 2013 issue of Clarkesworld Magazine.
The strap-on penises were apparently called "Firmies." You can read (and listen to an audio version of) the full story here, but here's a relevant extract:
The original product were the Squishies, and Julia is not at ALL shy about people knowing about her sex life (we have an instructional video, and she’s IN it) so I don’t mind telling you that she came up with it because her boyfriend at the time had a fetish for really large breasts, we’re not talking “naturally gifted” or even “enhanced with silicone” but “truly impractical for all real-world purposes like breathing and using your arms,” and conveniently at the time she was working at a company making top-of-the-line prosthetics with neural integration. She made herself a really enormous set of breasts and after a lot of futzing with the neural integration she got them to be sensate. Then the boyfriend dumped her and she didn’t really need them anymore, but her friend who’d had a double mastectomy said, “why don’t you make me a smaller set?” and that, supposedly, was when it occurred to her that maybe she could make this product to SELL. She found a manufacturing facility and office space, hired me and Juan, and went into the Fully Sensate Attachable Flesh business.
Depending on your predilections you may already be wondering why she started with boobs. IntelliFlesh is re-shapable, at least up to a point, and since I was the Customer Service department I started getting calls from people who wanted to reshape it into something longer, stiffer, and pointier.
“Julia,” I said one day, taking off my headset, “You need to start making strap-on dicks.”
“I can’t call those Squishies,” she said dismissively.
“So? Roll out a new line. Hardies. Dickies. Cockies. If you go with Cockies you can say ‘like cookies, only better’ in the ads.” Maybe I should note that one of the few things Julia doesn’t let me do is write the ad copy.
The Firmies were an even bigger seller than the Squishies. Between boobs and dicks, we had most users covered