In case you have not heard of this anime before:
"Plot Summary: Nice guy Kio’s normal life gets turned upside down when he meets a friendly, sexy cat-alien named Eris. She’s on a peaceful mission—and she’s ready to play. Things get even friskier when her fellow felines set up base in Kio’s house. It’s not all fun and games, though. Danger is afoot, thanks to several secret agencies and enemy dog-aliens on Eris’s tail. "
It isn't the usual harem anime you see now and days, as the plot and bad guys are actually well written and motivated. One such villain is an organization that wants a proper first contact with a alien species, and view the first contact with alien catgirls unacceptable and try to get rid of them through force.
For the game here, I am still pondering how to pull that off successfully. Naturally we can play the catgirl aliens, but how to fit that into having more then one guy in the roleplay. The catgirls eventually take over the male leads house as their embassy on Earth, so perhaps the men in the naughty roleplay could just be siblings and a father figure, and which ever friends they want to bring over.
Naturally, the alien catgirls have no sense of human decency when it comes to sex, and a number of times one of them almost sexually molests one of the human males. When they go visit the prime minister of Japan, they go wearing school swim suits since they learned that it was proper swim attire from a porn magazine.