As having partial ED in which because of meds I only hold a half erection when fully stimulated, and I love it personally. My mind and body may be screaming raging hard on, but physically it points straight out at best or maybe slightly hanging and I find this a big plus. I can spend as long as I want with a fully simulated erection without it physically tiring and if needed just tuck it in my pants and go about my business. Now if I could get it to ejaculate "on demand" I'd be happy as a clam.
Maybe prostate stimulation like wearing an anal plug would work?