You have been in desperate need for a long time, searching for some kind of miracle cure for your impotence. Your cock simply doesn't work. Recently, you came across a clinic nearby conducting experimental trials for a new medication for your exact problem. In your desperation, you sign up to be a human test subject for some of the preliminary trials.

You are at the clinic, the beautiful nurse explains the side effects to you and has you sign a release. This all seems pretty standard to you.
You are nervous but hopeful that soon you'll be able to have that orgasms you crave.

The nurse, after giving you the injection, begins to tell you a few more details about the, saying something about a stroking zombie.

At this point, you begin to feel overwhelmingly aroused with a deep desire to stroke your cock. Your cock is stiff as a rock. The nurse checks your heartbeat, you don't have one.

The medication has turned you into a stroking zombie.

The nurse explains to you that your only singular desire will be to stroke, and stroke, and stroke. You will never need rest, food, or anything else ever again.
You will only live to cum.

You're so lucky science has advanced this far, so fast!