As it is the interactive sex bit is definitely bare bones but IMO the answer isn't to add gifs or images. Newlife & Lilith's Throne both have similar text-only interactive sex scenes and they're pretty hot (Newlife more so than LT). The writting is this game's strongest suit so I'm sure the dev is capable of expanding what's already there. Add more variations depending on location and context, the traits & relationship of the characters involved.
For example in Newlife your sex partner's pace and attitude towards you through the scene depends on his personality traits & how he feel about you, from mellow and slow as he compliments you to brutal with no regards for your comfort as he calls you all sorts of names. Your character will react differently to penetration based on those things but also based on the size of their penis. At anytime you can chose to be a active participant or to just take it. If he's your boss, someone you hate, your lover, your bf's friend, etc or wether the scene happens in your couch, your bed, the club's bathroom or a backalley it will be brought up through the scene.