Yes, GUEST, that's the obvious translation, but it plays on double meaning of words when translated into German, and the less obvious meaning is:

When Caesar saw that the pisspot was full he pissed aside it.

You judge if that is similar to your example. I can do several things in English but understanding the jokes above is beyond my ability: Of hte poem McGrath has 'translated' I only got the before last line when I tried.

Wolfgang