Answer 1
It's rather impolite but still something you would want to know ... basically it's a warning that says that you stepped in some [poop]. More correctly the escrement is is one's trowsers. The idiomatic meaning would be, "you are full of it".
Answer 2
It should me mentioned that the sentence is grammatically wrong and the meaning is actually unclear. Saying something like to someone who speaks German would simply make you look like a fool.
"Du hast Scheiße an der Hose" would be a rather rudely phrased warning that you do have excrements on your trousers, however they might have ended up there. I can't detect an idiomatic meaning.
"Du hast die Hosen voll" (lit. you have your pants full) is idiomatic and means that you are a coward. On a similar note "mach dir nicht ins Hemd" (lit. don't wet your shirt) means "don't be a coward" or "don't worry" and I could probably think of a few more, but let's stop here. ;-)
To crap one's pants.
Your sister
"hast" is old English for the verb "to have". So "hast not" means "does not have".
Nicht mehr Hosen means literally No more pants. It would be used in a sentence like Ich werde nicht mehr Hosen tragen. In English this means I will no longer wear pants.
Today where is your
It means, "What does your family do?"
The grammantically correct form is Ich mache Deine Haare, which translates as I am doing your hair.
How old is your Auntie? Wie = How Alt = Old Ist = Is Deine = Your Tante = Auntie
Wie sieht deine Familie aus = What does your family look like
It means listen to your nose.
Ich liebe deine Füße.
"Herr, wir vertrauen auf deine Güte" means: Lord, we trust in your loving-kindness.
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