when a guy sees something he finds sexually stimulating and makes his penis become hard and he wants to fuck whatever it is

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

You penis's version of a thumbs up.

A boner is a long, pointy joystick that guys can get while feeling aroused.

Something you get in class. Fucking annoying.
Fixed by going to bathroom and wanking off, or flipping around between the pants and stomach.

when the blood from your brain goes to your penis when you see a hot girl.

What occurs when blood rushes to the penis, causing it to stick up. it is also possibly the worst thing to get before a school presentation.