That's the way I like it.

"Beg me to smack you in the face".  

I blink.  This is new.  But I do it.

"Please smack me in the face, Master".   He doesn't.

"More begging, then maybe I will let you come" he says.

I do.  I keep begging.  He doesn't hit me.

"Once I slap you, then you can orgasm, but not until then, do you understand?"

I nod "Yes, Master".  

I am begging again. "Please, Master...",  I want the slap more than I want the orgasm, somehow.    But I know when he does it I will come anyway; my body is conditioned, or my mind, both really. 

SMACK.   He slaps my cheek. I come, soaking everything. 

My head is lowered, but he finds an entry and slaps me again. And again.
My hands start to raise on their own to cover my face.  
Down, hands.
I will those hands back down again, grab the sheets to keep them down.  
Up, head.  
I raise my cheek to him.  I can't, won't, don't want to protect myself.  I'm all his. 

And again.