For starters one of the best feeling is taking him when he is still soft, and I can feel him getting bigger and harder in my mouth. When he is fully erect, it does have unique feel of thin skin over hardness. It is very soft, and some may describe it as silky, and although I wouldnt argue with them about this, I feel it doesn't really do it justice. My tongue will move over the soft skin and his ridged shaft will move around under the skin making it more difficult to completely describe the feeling.
My favorite part is the head. That has a whole different feel because even though it too has swollen up, it is obviously not as hard as the shaft. So now I've got two different "textures" in my mouth pressing against my lips and roof of my mouth. I'll sometimes squeeze the shaft just to feel it swell up just a little more. I truly enjoy how it feels rubbing against the roof of my mouth.
The smell and taste depend on the guy and when I get him. Clean, sweaty, the ultimate time to get him is right after a shower. I get his natural taste and smell. Little bit soap mixed with a musky odor. The taste is slightly metallic. Soap, body spray, can obviously change everything.
And when he cums. It is so incredible. I can taste his precum first, and it can be a but sweet in comparison to the taste of his flesh and my own saliva. The taste of his cum does depend on his diet, but it is a combination of bitter, salty and gives off a tange.
It also depends on if he is moving alot or not when he cums. Some guys shake and thrust so all I feel his his cum hitting mouth and his erection moving around. If he doesnt really move, then i can feel him pulsing. It is a very distinct feeling. Unlike when he flexes and it moves up and down, this is uncontrollable and it swells and jerks and then eases. I can count how many spurts and pumps he has. I can not feel his heartbeat though.