They're semi-rigid, not semi-erect.
I can't think of any pics of it that are online, but I have a friend who recorded a video of his after it was implanted. Doesn't look like a boner in the pants. It's malleable, so you can bend it into whatever position works best for whatever you're wearing that day. And they're pretty sturdy once they're bent into a position as well, so there's no worry about it moving on you. In the video, my friend straightened his out and then jumped up and down for about a minute. Still in the same position at the end.
