I've found these experiences embarrassing, and have never mentioned them to anyone, but thought that some of you here might find them interesting.
I can't really remember what, if any, particular thing inspired me to try masturbating anally the first time, other than that I had found a hard plastic vibrator along with a box of old porn magazines and a couple of 'sex-education' books, one of them I remember was 'Everything you Always Wanted to Know About Sex', when we cleaned out the attic when I was seventeen. They were in a large box full of old clothes which my parents were throwing away. I guess they never thought I would look through the box to see what was in it before taking it to the street. I'd never seen a vibrator before, though I knew what it was. It was white, about six inches long, maybe over an inch in diameter, with a screw-cap at the end which covered the compartment where you put in a battery. Putting the thought that this must have belonged to my mother out of my mind, out of curiosity, I kept it.
A few days later and my parents were out for dinner, my sister was at a friends, and I was on my back, naked, on my bed holding the vibrator against my penis and quickly bringing myself to a shuddering orgasm, then to two more the same way within the next half-hour. For the next couple of months I used the vibrator when no one was around (it made a buzzing sound I was sure could be heard outside my roon) to bring myself to orgasm once or sometimes twice after I'd masturbated to a first orgasm with my hands. I'd found that if I used the vibrator first, I'd get so excited that I'd finish within just a couple of minutes. Using it after I'd already orgasmed once would bring me wonderful sensations that I could keep giving myself for minutes before I couldn't hold back anymore.
On a Saturday morning shortly before I left for college, having the house to myself I was on my bed preparing to masturbate. As I said, I don't know what inspired me to try this, probably just having it there, but instead of squirting lotion onto my hand, I applied it to the vibrator, and laying flat on my back, I placed the tip at my anus and gently pushed it in. There was only the slightest bit of pain when the full width of the vibrator started to enter me, but I relaxed slightly and it suddenly slipped easily up inside me. I was surprised to find it felt nice, even before it was turned on, and for a couple of minutes I gently moved it in and out, alternately relaxing and tightening myself around it. Sometimes while I was doing this I suddenly had the urge to defecate and I would clench down on the vibe and once pushed it completely out of me.
Other times, as I moved it back and forth in me, I would feel, briefly, surprisingly pleasurable sensations. My penis had been half-hard before I'd started but actually softened a bit when I'd inserted the vibrator. Even when I had the pleasurable feelings, I didn't get hard, though my penis seemed to be getting more and more sensitive. After about ten minutes I stopped moving the vibe and instead wanted to try moving on it without using my hands. I had one of those big cushions with armrests you use to prop yourself up with in bed and I put that under my legs, and holding onto the arm rests, with my thighs draped over it, pulled it against my butt and began to hump my hips back and forth against it, alternately clenching and relaxing, and I was suddenly basically having anal sex, pushing the vibe in and out me. This quickly felt even better than what I was doing before, I reached down and twisted the cap to turn the vibe on and started humping against the reading cushion again. This time the sensations were much stronger and very pleasurable, and I began thrusting my hips against the cushion as fast as I could. I could feel the vibrations going through me and actually seemed to feel them in my penis, which felt wonderful.
Suddenly it felt soooooo good, as if I was just on the edge of orgasm, but unlike when I masturbated my penis, I didn't go right on to orgasm, but instead just kept feeling this incredibly pleasurable sensation in my penis and in my rectum. I had never got hard this whole time and my penis was now flopping back and forth against my belly and my thighs as I worked myself back and forth on the vibrator lubricant. My glans was leaking pre-cum and felt extremely sensitive, like it did just after I'd orgasmed, and I was afraid to touch it. Each time it would slap against me, it sent shivers through me. The sensation was somewhat like the feeling I'd experienced just before orgasm, but also very different. It was, however, at least as pleasurable. And it kept going. I really couldn't believe it.
I kept thrusting against the cushion for some time, I really don't know how long, but it wasn't just a couple of thrusts, and then the feelings got even more intense and I thought 'Oh, wow!' I was going to be able to orgasm without ever touching my penis and without my penis ever getting hard. I tried to hump even faster, and squeezing down on the vibrator. My penis finally began to slowly stiffen, and the feeling intensififed even more, but then still only semi-hard, I just began to cum. I started ejaculating before it happened, but then I was right in the middle of the most intense orgasm I'd ever had. It was so good I stopped thrusting and just clenched down on the vibrator and then began to tighten and relax my muscles alternately around it, and I kept right on orgasming! Rather than feeling those ecstatic spasms as I ejaculated, my semen just flowed out of my penis onto me and I was feeling just one constant sensation of ecstasy. It felt like it went on for a long time, but it probably wasn't more than a minute, but that is pretty long for a full-blown orgasm before it even starts to subside. I was amazed and absolutely loved it. When it began to subside, I began to gently play with my penis, and it felt almost as good as it did when I was thrusting my hips but the sensations was now only on my penis. I gently squeezed and stroked myself, still mostly soft for another couple of minutes until the sensations finally had all faded away, then I just lay on the bed, limp sweaty, covered in semen, and absolutely relaxed.
I was sure I'd found masturbation nirvahna. But that was not to be. Two more times, when I had the house to myself in the last two weeks before I left for college, I tried to repeat the experience, but no luck. The same way I'd done it the first time, or on my stomach, or riding the vibe upright, straddling my reading cushion, I could not bring myself to orgasm the same way. Each time I tried, I'd get about half-way there, the feelings as good as they'd been during the middle of my first session, but never any better. Instead, after maybe fifteen minutes of really trying to get there, the other times I started to lose the feelings and I just grabbed my penis and masturbated myself with the vibe in me. Both times I got almost hard and then came with a more-or-less regular, but intense orgasm, the first time laying on my side, the second, and last time I did it, on my knees astride my reading cushion. I remember being able to feel myself clamping down on the vibrator as I ejaculated in spurts, and the sensation being so intense it was almost uncomfortable. Almost, but not quite.
I was disappointed that I couldn't give myself the same incredible orgasm I had the first time, although the other two times had been fun, and before I went to college, I threw the vibrator away. I couldn't imagine having the privacy to do it like that again living with roommates, and I thought it would be pretty embarrassing for a guy to be caught with a woman's vibrator. So that was the end of my experiments with anal masturbation for about six or seven years.
I was 25 when I tried it again. In the interim, I'd never even really thought of trying to do it again, probably because I didn't have a vibrator, and because the last times I'd tried it, I couldn't orgasm. I don't know why I thought to try it anally again, but I did. I'd just cleaned the bathroom and had stripped for a shower. I was planning to masturbate under the shower spray, when I thought (now this is what I mean by embarrassing) to see if I could use the mop handle. I took some hair conditioner and lubed both myself and the end of the mop handle, then got down on the floor, face down, with my thighs, and hips on the cold tile, resting my upper body on my forearms. I put my penis against my belly, so it was pointing toward my head. I pulled the mop handle up between my legs, and placed the tip against my anus, and holding it steady with calves and ankles, gently pushed back onto it. It was thinner than the vibe and slid right into me. I held still for a moment, then began to gently move my hips, making it slide in and out of me just a couple of inches. That was all it took. Immediately, I felt the most pleasurable sensations, and I began to clench my muscles inside and my butt cheeks around the handle. I barely had to move at all, just clenching and relaxing my muscles had me nearly to orgasm in just a couple of minutes. I was resting on my forearms and my penis was against the floor but I wasn't humping or sliding against it, the sensations were all from the broom handle. I stopped moving then and clenched and relaxed, clenched and relaxed, and felt the sensations intensify, then my penis began to harden, and I felt myself starting to ejaculate, and I was orgasming. Again, like the first time, once I got there it was incredibly pleasurable and kept going and going. I moved my hips a little, back and forth, and the feeling was even better. I was blown away. I lay almost still on the cold tile floor of my bathroom, and had a wonderful orgasm again, for maybe a minute or even more trying to keep quite, while my roommate was cleaning the kitchen outside the door, not twenty feet away! If he had walked in on me, I think I would have died.
I tried again with the mop handle when my roommate wasn't around several days later, but, no orgasm. I had to reach underneath me with conditioner in my hand and orgasm thrusting into my fist.
About six months after my orgasm with the mop handle, my roommate and I and an old friend of his who was visiting were talking about what we'd done sexually, and my rommate asked me if I'd ever done anything with another guy. I told him about a friend and I, and he was surprised that we hadn't done it again. I told them about the vibrator when I was 17, but not about the time with the mop, which was just too strange to tell him about. He said it sounded like the kind of orgasms he'd had with his friend.
I've tried masturbating anally a few more times on since then, using a C-cell flashlight I have, but I've never quite been able to get there again and ended up using my hands each time.