You pull off in time

You gather your sense just in time to pull off his lap. You can tell by the way he groans that he is disappointed, and frankly, so are you, but this is the smartest thing. You cannot risk getting knocked up by your best friend's boyfriend. As a consolation prize--for both of you--you quickly go to your knees and wrap your lips around his shaft, sucking it fast. You can taste yourself on him. Your juices mix with his musk in your mouth and almost overpowers you. It's not all too bad, you think to yourself.

You suck him all the way to the base, then alternate between kissing his head and pumping his cock with your small fist. He starts to buck after a minute of this. His hands clench the edge of the toilet seat and you look up at him, encouraging him. "Yes, Jack, cum for me," you purr in your sexiest voice. It does not take much because he explodes, shooting his cum all over your face. You close your eyes and open your mouth, catching two of the streams on your tongue. Unlike when you give your boyfriend a blowjob, you quickly swallow Jack's cum down. A couple of other threads of his seed land on your cheek, nose, and chin.

You lick your lips and once he is done shooting you clean his cock with your tongue, giving it one more stroke with your lips before standing up. "God, John, that was so hot. So much better than Stacy," Jack says as you wipe your face clean with a tissue. You then quickly start to get dressed after drying up some. Sliding your panties up your legs, you reply, "Just remember, let's keep this our secret." Before pulling the rest of your clothes on, you lean down and give him a long kiss, making him taste what you had just tasted. Then you pull back and whisper, "maybe we can do it again some time." With that, you put on the rest of your clothes and leave the bathroom. Jack just sit there somewhat stunned.

Problem was, you had still yet to get off yourself. And now, you were especially horny from riding and sucking off Jack. You could go back and demand he finish you up, but in his state, you doubted that he would really be much help. And with him in the bathroom, you couldn't just go take another shower. Maybe you could try waking your boyfriend up? You heard some groaning coming from the bedroom now. He must be stirring in his sleep or something, so maybe he could be stirred awake. Or, you could go rejoin the party.