buttock [noun] [de bil, de billen]
"Bil" is mainly used in relation to the human body, though animals can also have "billen". The latter would be translated with "hams" in relation to a cow for example. In general, the plural "billen" is more often used than the singular "bil". The "billen" cover more than just the buttocks area, but also a part of the upper thighs. In daily practise however, it is a synonym for the bottom/buttocks/behind.
It is quite acceptable to use the word "billen", but if you want to be on the safe side, use the word "achterwerk" which is the formal Dutch equivalent of "behind".
– "De baby zat met zijn blote billetjes in het zand."
("The baby sat with his bare (little) buttocks/bottom in the sand.")
– "Frank klaagt altijd over de dikke billen van zijn vrouw."
("Frank is always complaining about his wife’s fat bottom.")
– "De moeder gaf het stoute kind een flink pak voor zijn billen."
("The mother gave the misbehaving child a good smack on the bottom.")
– "Een blotebillengezicht": a round, smooth face (babyface).
– "Van bil gaan": <slang> to have sex, to get it on (sex involved), to go at it.
– "Wie zijn billen brandt, moet op de blaren zitten": as you sow, so
shall you reap / as you make your bed, so you must lie on it.
Literally: one who burns his buttocks, must sit on the blisters.
– "Met de billen bloot gaan": to come clean (lit. to go bare/naked with the buttocks).
– "Reet": <derogatory slang> ass. "Reet" is actually an old-fashioned word for "crack".
– "Hol": <derogatory slang> ass. Literally the noun "hol" translates to "hole" (like a fox’s hole).
– "Kont": ass, bottom. This word and the two previous examples have no plural.
Here a common informal expression is: "Lekker kontje!", which you can use for either a male or female butt that you think looks good 😉
– "Achterwerk": <formal> behind [noun].
– "Kikkerbillen": frog’s legs (French delicacy).
"1 april, kikker in je bil!" is an expression that is often heard on April Fool’s day. The expression has no special meaning (other than the literal frog in your behind), I guess it just has a good rhyme to it 🙂