Play with them of course...

You take a deep breath as you move your hand over her tit...

"This is it John...." You tell yourself as your palm comes into contact with her skin...

The feeling if her breast in your hand makes you shudder, and you decide that you can't wait to jerk off any longer... You free your cock with your spare hand and begin to stroke it, gently squeezing her tit and imagining your ramming your cock between the large mounds of flesh until you cum on Sarah's face...

It doesn't take much from that line of though until your feel your dick twitching...

The only question is where to cum...