I do this all the time in the shower. It feels amazing!
I was at home alone for the entire night because my parents were at a hotel for their anniversary. I already knew that I would spend the night masturbating.
I have just recently found the joys of anal insertion, and I usually use a cucumber with a lot of lube when I masturbate. But this time, I decided to try something different.
When my parents left, I put on a pair of my dad's white briefs, and walked around in those for a while, sometimes playing with my tight ball sac, massaging my anus, etc. I was rock hard and ready to play. So I got into the shower with a new plunger my mom had just bought. I laid down in the shower/bathtub, turned the water on, grabbed the bottle of shampoo, and started to rub my cock with it, massaging my ball sac and scrotum. The pleasure was already intense from all of the playing I had done earlier.
The next thing that I did was lube up my fingers, and started to stretch my hole open by sticking one finger up there, then two, three, and ended up with all five fingers in my hole. I took them out, squeezed some shampoo into my hole, then crammed the end of the plunger up my ass. I pushed it up as far as it would go, then let the other end of the plunger rest at the end of the bathtub.
I continued to massage my rock hard, seven inch penis slowly, building up the pleasure and anticipation. While doing so, I was moving up and down, so that the plunger handle was going in and out of my hole. This made it feel much better. When I could feel myself about to cum, I stopped, then started again. This went on for about half an hour, until I couldn't take it anymore. I finally fell as hard and as fast as I could onto the plunger, and let myself go.
The pleasure and stimulation was so great I couldn't help but to yell and start moaning. When I had finished cumming, I took the plunger out, washed it, then repeated. It felt so good.
I hope that you all enjoyed my story as much as I enjoy reading everyone elses. I will write later about how my dad catches me doing this at a later time...