Fun game, also here is some suggestion:
Currently the combat is not really challenging, maybe a stamina system would help improving it more? Each action (or/and self-orgasm cost stamina) 0 stamina makes you lose control of the battle and get raped and killed instead; so wisely use the actions, and decide when to orgasm to unlock ultimate drain. And with leveling up, your stamina will increase.
For further development, if possible, will you add more specific sex acts as skills (foot/blow/boob-job, missionary, doggy, etc...). Those can result in more variety of gameplay. For example: Have different types of enemies that have different traits affecting their "arousal" to different sex acts and certain resistance to certain positions. For example: an enemy who is more vulnerable to feetjob, and have resistance to boobjob; or an enemy who has a huge penile so he would cause more damage to vagina penetrating acts (which means faster to orgasm, damage to stamina as mentioned above); or an enemy who is more engaging in sex acts (they actively use a wide variety of "sex technique" on their turn to make you orgasm faster), or a combination of those, etc... To make them special, you can also chose only certain types of enemies to have the traits such as bosses, high level enemies.
The skills can be obtained by leveling up, or through certain training type npcs... (it's up to you to develop)