To fuck, make love.
Also: verneuken, which means to fuck up
Ik ga je anaal neuken vanavond, means, I will do you in the butt tonight.
To screw. Mess with. Dutch use it most often in casual manner, though now famous in Europe as well.
Neuken in de keuken met mien Schatje. - Dutch. , Don't ever neuken with that pussy.
literally means "to have sex in the kitchen" in dutch. But Dutch people always tell tourists that it means "hello" in dutch. It is a very commonly used expression, Dutch people being great fans of kitchen sex. Probably the second national sport after cycling.
Tourist entering a restaurant in the Netherlands:
"neuken in de keuken, could we have a table for two please"
tourist in a restaurant: wil je neuken in de keuken, mag ik wat melk?
ober: ja lekker aaaaaghhhhhhh