Hum..tough question because it's on of my favorite things to do to my boyfriend.

I like to hear the different sounds he makes from his breathing becoming erratic to hearing
him say things like Oh my God and Oh baby it feels so good,etc..
I like taking my time with it. I'll tease right underneath the head with the tip of my tongue applying pressure and sucking,then some deep throating(which is then i hear him suck in his breath, coo,and ooh sounds)
Of course by then i'm soaked but continue working my tongue away on him to lick and suck the balls as well,including the licks of the tant.
Just knowing he loves what i'm doing to him and the response i get gets me thoroughly soaked,so what's a girl to do but continue bringing him close to climax each time by repeating with more stronger strokes and suction until finally i know he is on the brink and it's then i take him in my mouth to swallow like a good girl.
Of course i check after for any lil mess i made,but i pretty much always get it all,unless he wants to shoot it on my chest.

I love the way it makes him feel and react,of course giving is just as important as receiving,which my boyfriend reciprocates alot,but sometimes i just like to surprise him and want him to know sometimes i just like to give it to him because i want to and he inturn will do the same to me by just wanting to please me sometimes without expecting anything thing in return. *SIGH* Now i'm horny,lol.