Sentence:  Is whispering nothing? / Is leaning cheek to cheek? is meeting noses? / Kissing with inside lip? stopping the career / Of laughing with a sigh?—a note infallible / Of breaking honesty—horsing foot on foot? / <WSD>Skulking</WSD> in corners? wishing clocks more swift? 
Meaning of the word marked with <WSD> tags:  To stay where one cannot be seen, conceal oneself (often in a cowardly way or with the intent of doing harm).