I suspected I was really into this after a visit to my university's clinic, years ago. I'd gone in because of sharp pains in my rectum. A lovely MD in her early fifties asked me to lower my pants and lie on my side so that she could "get a feel of" me. Her gloved and jellied finger inside me felt wonderful, despite the electric pain when she touched my prostate.
Years later, I found just how much I was into receiving a finger inside me. In one of my sessions with a female licensed massage therapist ("Sirena," whom I've posted about elsewhere) — who was *very* open-minded — she introduced me to prostate massage.
Early in that session, I was face down and naked on her massage table. The sheet was already gone. Sirena was massaging my hips, which was always heavenly. She surprised me by saying, "I'd like you to raise up and get on your hands and knees."
I remember thinking, "*This* is new!" But of course, I complied.
I heard her put more oil on her hands and rub them together. Then I felt her place her right hand on my right hip, then use both hands to spread my cheeks. I felt my anus open and let in the cool air.
I could feel Sirena leaning in, and for a moment, I wondered if she were going to kiss it.
She didn't, but she did blow air from her lips, to caress my sphincter in that way. Then I felt her oiled fingertips touch my ass lightly, then start making circular strokes there. It felt so good that I couldn't keep from rocking my hips a little.
She whispered, "Let me know if this is OK," stroked my anus again, and then gently and slowly dipped an oiled finger inside me, with a slight corkscrew twist. I remember that it burned slightly, and I spasmed, but it felt wonderful, as she dipped her finger in and out, and I told her, "That is VERY ok."
We fell into a rhythm, with her penetrating me, slipping out and back in, me rocking slightly, and she soon started slipping two fingers in and out, and using her left hand to stroke and tug on my oiled balls, with strokes to my perineum, at the same time.
I was breathing hard and rocking against her firm oiled fingers as they came in, and felt a few drops of pre-cum dripping from my stiffening cock onto the massage table. It still burned a little (it made me think briefly about a novel I'd read, where the American male hero is raped by a ninja, and how the penetrations burned), but unlike Nicholas Linnear, I was in heaven.
Deep inside me, her fingertips found and circle-stroked, then pressed against my prostate, which felt electric, though somewhere halfway between pleasure and discomfort, at first. It felt a little like I needed to pee, and I spasmed against her fingers, again, but she kept stroking and whispered, "Shh. It's OK."
More pre-cum leaped from my glans. I felt her left hand catch the drops and use them as lube to start stroking my cock, as she continued to press rhythmically at my prostate.
I usually didn't cry out when cumming, especially not at her clinic (she didn't want her secretary to know what was going on), but I did that time. I came against her fingertips in my rectum at the same time that I came with my penis, shooting all over the sheet. I dropped down and she held on while I did so, her left hand smoothing my hot cum across my belly, squeezing me there, and then sliding up to insert one cum-slicked finger into my ass.
I was literally gasping, and I said something like, "That was like being male and female at the same time." She "mmmm"ed in response, then patted me on the hips, removed her finger, stroked my ass one last time, and went to wash her hands... then returned with hot washcloths and wiped and scrubbed me down.
As she was toweling me off, Sirena mentioned, "That's not for everyone. But I could tell how much you enjoyed it. We can do it again next time, if you want." So that was the first of many times Sirena penetrated me...sometimes, with me on my back, holding my knees.
Weeks later, thoroughly hooked on our new 'routine,' I asked Sirena whether she would fuck me with a strap-on. She said that she would have to draw the line, there, but recommended that I try a prostate massager, while masturbating. I ordered one, and found that the climaxes that come with having my prostate vibrated while I jerk off, are orders of magnitude more intense than usual. Highly recommended.