Ninja sex is a more complex form of stealth sex. Once you have tasted a woman, and are no longer a 'tiny grasshopper', you learn that sometimes you have to be quiet while enjoying your partner. This is not being dead silent during sex, but stealth sex. Roommates or other inconvenient situations necessitate the use of stealth sex.

Once this level of prowess has been maintained for a while, some get the urge to perfect their art. This brings them to discover new possibilities, and to progress to ninja sex. Now you are no longer just doing it as quiet as you can so you don't wake up the roommate sleeping in the bunk below you. No. Now you revel in your abilities, and attempt new, and oftentimes difficult sexual positions, all the while maintaining near complete silence.

It has been whispered that years ago, the great masters of this art could faultlessly execute their forms, even with non-sleeping roommates in the room.