That really does feel good, both physically and emotionally. Having the LOVE OF YOUR LIFE penetrate your "forbidden place" is to me an ultimate show of love and trust. But when she uses her own body's lubricaton, it makes it even that much more special. And just like Nikki said, you'll probably get goosebumps and cry out loud when you have that unavoidable explosive orgasm. My second girlfriend did it to me twice. But I would love for my wife to do this for me sometime soon.
When I was 20, I dated a 25 year old chick named Andrea. She was the kinkiest partner I've ever been with to this day. One evening she was sitting on the couch naked, and asked me to walk up to her. She pulled down my shorts and underwear, then had me slip them off the rest of the way leaving me completely naked. She started giving me a handjob and it felt good. I looked down at her, and she was masturbating with her other hand. She looked back up at me and said "I'm going to give you something new and special baby." I didn't know what she was getting at, but she started picking up the pace stroking me. I was super aroused, but not quite ready to come. I was looking up at the ceiling, marveling at how good her hand felt. All the sudden, I felt her other hand go between my legs, then a slippery finger went between my cheeks and plunged far up my rectum. I gasped out loud...."NO HONEY!!" She said "easy baby, easy...I know it's a little uncomfortable now, but you're gonna love it, trust me". I had involuntarily tried to block the insertion by closing my legs and squeezing my cheeks together. Too late for that, her right index finger was up me as far as she could get it. It really didn't hurt that much, thanks to her own vaginal lubrication, which is as good as K-Y. It happened so sudden, and I'd never had a finger up there before. She slowly used the soft pad of her finger to massage me internally, withdrawing a little at a time until she was inside me up to her second knuckle. Then the magic happened. She arched her finger back toward my penis, directly up against my prostate. I gasped even more this time, but with pure joy. I'd never felt anything so intense. I relaxed immediately, and she got more vigorous with that finger. She literally milked me. I'd didn't know that us men could anatomically do such a thing, but lots of clear fluid started oozing out of my penis. And I hadn't even ejaculated yet. Andrea looked up at me real sultry and said "feels good doesn't it hon." I couldn't answer, I was in total ecstasy, but she could tell she was doing the job on me by my breathing. She jacked me furiously, and with one last firm pull of her finger I spurted all over her breasts until I nearly lost control of my legs and collapsed. That was amazing, and I've loved prostate massage ever since. Through anatomy studies, Andrea had learned that a man needs to have his prostate drained every so often to help prevent cancer and urinary problems. And other than the experience being physically fulfilling and intense for the man, it also helps bring him closer emotionally to his female partner. I'm inclined to agree, and my wife now does this for me from time to time. I'm very thankful for it each time she does it.