Perfect woman. One you would make yourself.

To build a piano is a suggestive term usually uttered in conversations amongst men referring to an act done to a women. Building a women's piano does not refer to any specific act rather it is a desired reaction out of a women through sexual stimulation. The term was originally formed after gender walls began to break down in the early 1900's as women began to insert themselves in different parts of society including in music. Men began to credit women with having very impressive musical talent comparative to that of a man and soon terms such as these began to form. Knowing this makes it easy to see how the saying came about because obviously women create beautiful passionate sounds that have uncanny ability to arouse and stimulate the opposite gender and there is striking similarity in the sounds made from a piano compared to a women's sounds of arousal and stimulation. Many compare a women's passionate and mildly aggressive sexual outbursts to music and some feel they are one in the same. In short to build a piano is equivalent to forcing a women to have a powerful orgasm.

You forgot an L

Being self conscious by your build in Minecraft

When some one saves all the nasty voicemails or texts you have sent them. Or records the fight that you've had.

It means jerking it. You know, MASTURBATION.

having a boner under your jeans