You take matters into your own hands.

You feel an immense wave of gratitude towards Karen for your recent changes. Its time to repay her, you think. Before she can do anything, you pull yourself up and push her down in front of you.
She grins up at you; "Ooh yes! This is more like it!".
You ram your tongue down her neck and she responds in kind, her hands writhing between your shoulder blades. Then, one hand behind her for balance, you put two sharp fingers against her clit and begin to massage generously. You pull back from her mouth to watch her face and breasts as she gasps in pleasure. Then, you shuffle up so that you are looming large over her and have both hands planted either side of her head. Here you penetrate her deeply, to which she squeals in pleasure, wrapping her strong legs around your waist to try and draw you into her even more. Then, slowly at first, you push in and out making sure that every stroke hits the right spot. Her eyes seem to cross slightly and she arches her neck back, her hands scraping at the floor, unable to bear the overwhelming feeling of pleasure. You plunge harder and faster, eliciting an exciting back arch from Karen, perky breasts pointed towards the ceiling.
"Ohhhh myyyy godddd..." She moans, her head lolling from side to side.
Then, as you feel the both of you approaching climax you yell; "Don't you dare cum yet!" And pull your member from her moist vagina, shooting your load all over her stomach and vulva. She snaps back to you with hateful eyes and an animalistic hiss, which almost makes you come all over again, but follows your command. Quickly you slide back and clamp your lips to her labia. Then, using your teeth to form an open passage (and for additional stimulation), you plunge your tongue deep down her vagina. Karen arches up, a muffled scream of ecstasy escaping her lips as she runs her fingers through your hair, all while pressing her breasts into the back of your head. You move up so that the thick part of your tongue has heavy contact with her clitoris, which causes her to buck and sway even more. Then, in addition to your tongue action, you begin to bite down on her clit, hard.
"Oh shit!" She screams to the ceiling, hand gripping your hair tightly. She writhes away unable to bear the intense feeling, and with her new found strength its an effort to keep your mouth on her. But you manage it, and with one final heavy bite, you feel her orgasm erupt through her frame. You let her free and watch her cum stained body writhe and quiver as waves of orgasm shake her from head to toe. She reaches out to you, the floor, even her tattered dress. Finally, the pleasure ends, and she sighs deeply, a smile of perfect satisfaction spreading across her face. She looks up at you and you feel a very real sense of affection emanating from her. You stand together. There is a slow clapping sound as you turn to see Gwen walk gracefully to the centre of the room.
"Well, well Linus, you will have to teach me that one. But later, now we have business to attend to."