Invasion of the Boobie Snatchers

"An average college student gets a lesson in intergalactic sex when he awakens to discover a horny alien cat-girl in his bed in an out of this world hentai that proves just how compatible humans and aliens really are. Determined to teach his new extraterrestrial lover Yuria all there is to know about sex on planet Earth, Shinji finds that he's not the only one having a close encounter when Yuria's lusty sister Alissa arrives from the mother ship to find out what really turns mankind on."