En sentido figurado... / Figurative Meaning...

 I just wanna start saying so sorry if today's joke it's so bad or missunderstable... It's some kind of hard to write some strips or to translate some joke to english 'cos I don't get a lot of idioms, so... if anybody could help telling me if the joke is understandable (and funny) or if there's some other way to tell it better... I'm at your feet :)
Thanks beforehand!
 And, once again, sorry for my poor english :P