I've had to have them for medical reasons, and they aren't enjoyable. The first time I had one, it hurt incredibly much. The most recent time, it was less painful, and felt like someone was using a joystick inside me to play a video game. But both times were because I needed them medically, and I consented. I was not coerced. I consented, based on my doctor's medical opinion of the necessity, and that makes all the difference.
Without consent, it's just rape.