You're so hard already! Tell you what, when you're about to cum, and ONLY when you're about to cum, I take my hand away so you can cum to my tits. But the catch is: you're only allowed to cum when I tell you to! Not before, not after, only when I tell you to. So go on, start stroking yourself, nice long and hard strokes. Get yourself all nice and hard and aching. Go on, speed up, harder, harder, harder! It would be such a pity if something were to happen and I don't tell you to cum, wouldn't it?