I found that although tight, I can insert a triple A battery entirely into my urethra. It has to be sterilized with alcohol, and well-lubed. I find there is a restriction about 1 centimeter beyond the peehole, but with patience, I stretched it, and pushed past that. I felt the tightness of the battery sliding in. There was a minor stinging sensation, but very slight.
Using my fingertip, I finally pushed the battery all the way into my urethra until it entirely disappeared from sight. It felt great. I walked around with the battery in my erection for a few minutes. I could feel the extra weight. I did keep checking that the battery wasn’t sliding further down into my cock. I think it’s unlikely it would get past my sphincters, but still, it was a concern.
Finally, I jacked off with the battery still in and it delightfully blocked my cum.
After I settled down, I pushed on the bottom of my battery, through the underside of my cock. It took a moment but then the battery reaappeared, followed by the remains of my cumshot. For the next day, peeing stung a little bit.
I’m going have to do this again someday soon, maybe with two batteries next time.
For those who are interested in this sort of thing, you might enjoy Personal Experiences with Sounding