There are three levels of arousal, not three orgasms. It is impossible to time it correctly, even with the cheat - there are 7 levels of the red bar on the penis, and 10 levels of arousal on the last heart (assuming you're using "high" thrust speed). If you release the "s" key after the first three levels of the last heart, you'll still ejaculate early - there's no special scene, it's just the ejaculation event takes priority over the girl's orgasm event.
By the way, it's easy to let the girl come first - just use "low" during the first heart, "medium" during the second, and "high" during the last. Simple enough, and an obvious strategy.
... did I just analyze the mechanics of a flash sex simulator?
It's not a cheat, you're supposed to press "S" to reset the timer.
To win the game you have to cum using one of the three different choices, right before the last heart fills on her third orgasm. You'll know when it's time when she makes this face: XD
If you press the "O" key you can instantly take her to the third stage of arousal. Is there a win scenario to this game at all or is it always the same?