I came across this joke on necyklopedia and it's a simple "In Russia" kind of joke.

So: in Russia, the toilet pisses on you.

and tin (Sn) is lead (Pb)

Text on the poster:
Целься точно и не промахнись
Tsel'sya tochno i ne promakhnis'
Miř přesně a nemiň
Aim precisely and don't miss

The poster has a double meaning and it's supposed to be another joke, if it wasn't already clear .

Sorry but the English language is awfully flat when it comes to swearing/cursing,
you really cannot come up with anything other than "Fuck", like you call that swearing?,
amateurs.