There are multiple things you could do. Have seen simelar stuff in other games like this.
1) Birth effect. (This may be an inaprobiat thing) The player get pregnat after a timer runs out he gives birth to same enemy. 2 things happen:
-Player is stunned for multiple secounds, so he can give birth
-Payer has an extra enemy to fight
+Player may get horny
2) Damage effect. Just take damage after having an orgasm. I would dislike the feature, cause it will stop players from getting into such scenarios. And it kinda jumps around not shoing nsfw-animations. What is kinda stupid.
3) A new source of heal. Maybe put less beens into the game, and basicly force the player to take the slime. But there is a catch, if you use it to often, you may get:
-Mindbroken: The player has now basicly lost. He is only a husk after 2 much stimulation.
-Take Damge: Be sure that you do more damage, than the total amount healed or it will still be an infinte healing source.
-Debuff: Player is healed now, but takes more damage.
Or maybe make it bonus hp. Basicly giving the player on top of max hp 20% more hp. wich means that the slime also only can heal this +20% health and not more