Your mission in Stroker is to reach the ultimate orgasm.
The game "play" went into different phases, the first one by reaching an erection by moving your hand up and down at a defined rhythm. Later on you start rubbing your penis using the joystick up and down.
Much like in real life, things like premature ejaculation may happen and you would have to slow down or pause your rhythm to avoid the inevitable.
On-screen you are presented with a hand holding a penis. To start off, you must achieve an erection, this is done by moving your hand up and down at a medium pace. You'll know when you are getting close because the penis will flash all different colors, red means he is just about to let off, so you'll need to hold back for a second or two. You can also tell when to hold off by looking at the guy's face in the top left-hand corner.
You score is judged on how good your orgasm was. There are six "ratings", these are: Rotten, Bad, So So, Fair, Good and Great. Obviously, the longer you manage to go for, the better your score will get.