If you force or offer them to NPCs during sex, etc., their effects will temporarily change them. You can make the changes permanent by then feeding them a MorphIn pill, later. Once you've discovered enough pills, tested pills, and unlocked/purchased new features in the lab, you will not only be able to manufacture more of the pills you've discovered, but also you'll be able to make "custom" versions of the pills with effects you control. For example, the default BoneRoll gives a random dick. Later on, you can make a BoneRoll that gives a specific dick and length. c: