Yes, as written in the message you receive after leaving the storehouse, you need to kill these enemies (in a non-sexual way), so that they drop D. Cum. After that, you can go to the bonfire and evolve your character. At first it seems difficult, but it becomes quite easy when you improve correctly. In this version, I recommend this equipment together:Do we need to actually defeat the enemies? I just fight until I can make them cum and then they run around with a cute little heart above their head.
In battle, you first use the “Workout” skill from the Dumbbel Kit and then the “Ultrapink Vision” from the Synthetic Body. Remember that the latter scales with M. Attack, so it's a good idea to upgrade this attribute at the bonfire.