Wat kan ik zeggen? Poster. Patat in een toilettas. Patatas Toilettas
This joke is Dutch only. I could explain it in English, yes, but... do you know the feeling when someone really thoroughly explains a joke? And when you get it, but don't find it funny, you are obligated to laugh? That's not what I'm going for here. I just saved you from the awkward trouble this joke could have been. I saved us both.