There's certainly a buildup of sensation and feeling. Some of it is similar when masturbating -vs- having sex, some of it is different.
There's a feeling of pressure that's not there at the beginning that slowly builds the closer I come to orgasm. And my cock gets more firm (no matter how hard I was before, I'm always a bit harder as I near climax).
I get a wierd sensation in my chest and the lower part of my neck that's hard to describe. It's somewhat similar to the feeling I get when I have to throw up or panicked, but it's intensely pleasant instead of discomforting.
When I'm masturbating, I'm always in control of the situation. I pretty much decide when I've edged for long enough, and when I'm going to cum. I don't rush it unless I'm in a hurry for work, and otherwise just enjoy it for quite some time.
During lovemaking, control is much harder to maintain. Even when I'm on top, there's an animalistic sense of urgency to cum, and cum
inside her, that gets very hard to ignore. It's instinct, and nature, and it's both difficult and fun to fight against it and see how far I can go before I lose the fight. I can get forceful when I'm close to cumming too. Not in too bad a way, but that's prime time for pinning her down against the bed and thrusting hard & deep. I haven't ever gotten too rough, but I can get a little insensitive towards mild discomfort in a way that I'm normally not.
If she's on top, all bets are off. The best orgasms I've had are with woman on top of me, bouncing up and down passionately and forcing it out of me while I struggle to hold back. When my brain and body are out of synch like that... with my brain unwilling to cum yet, but my body unable to stop it, that makes for some crazy intense orgasms.
So anyways, that moment of climax I feel pleasure burst through me. It lights up just about every pleasure receptor I have from my waist on up and
(NERD ALERT) I feel like one of the programs in the original Tron when they drink from that river and energy just flows through them and they start glowing brightly all over. I can feel the cum shooting out of me, not just from the tip, but I can feel it inside my shaft, forcing its way through me. The harder I cum the more I can feel that internal pressure as it makes its way out.
The feeling is short lived, but wicked awesome, and then afterwards I need a few to recover, laying in her arms and breathing heavily. Sometimes that's the end of it, sometimes it's the start of round 2 or 3. Depends a lot on whether or not she's finished or in the mood for more.
(The best I could find of that Tron scene, which is not a very good quality, is at timestamp 3:03 in this:
Tron - I'm Blue - YouTube just in case you don't know wtf I'm talking about).