I would love to know a couple who insists on both. While she is still quivering from his fucking and able to achieve a second or third orgasm, I would go down on her and delve in deep, licking out all the thick white sperm, letting her squeeze it out of her on my tongue, licking all of the juices off of her clitoris until she achieves another excited orgasm.
Then when he is watching me enjoy the taste of his manhood, resting up from his orgasm and starting to get worked up for another round, I would turn around and cleanse his cock with my mouth, tasting the results of their first union, taking any stickiness off of that presumably brown shaft and getting him fully hard, so that he can enter her a second time and fuck her nice and slow until she achieves a third orgasm. Then we can start the cycle all over again, continuing well until the next day and everybody is completely wore out.
The great advantage of having multiple sex partners is how long you can keep going trying different positions and performing various acts until everybody's libido is truly satiated.