I leave one sat expectantly in front of Parsifal with opera glasses (3)

I believe the answer is:
poo
'i leave one sat expectantly' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'front of parsifal with opera glasses' is the wordplay.
'front of' suggests taking the first letters (the letter at the front of the word).
'with' says to put letters next to each other.
'opera glasses' becomes 'oo' (I can't explain this - if you can you should believe this answer much more).
The initial letter of 'parsifal' is 'p'.
'p'+'oo'='POO'
'in' is the link.
Can you help me to learn more?
(Other definitions for poo that I've seen before include "Expression of disgust (at, eg, bad smell)" , "Expression of disgust; sounds like bear" , "number two?" .)
