with bated breath (?.)
- abjectly
- anticipatingly
- anticipatively
- anticipatorily
- anxious
- apprehensive
- apprehensively
- aside
- bashfully
- behind the curtain
- behind the scenes
- behind the veil
- between the teeth
- covertly
- diffidently
- expectantly
- expectingly
- fearfully
- for fear of
- hopefully
- humbly
- in a corner
- in a whisper
- in an aside
- in darkness
- in hidlings
- in secret
- in suspense
- in the background
- in the dark
- keyed-up
- meekly
- modestly
- mousily
- nobody the wiser
- on all fours
- on bended knee
- on edge
- on tenterhooks
- on tiptoe
- out of earshot
- quakingly
- quivering
- secretly
- shrinkingly
- shyly
- sotto voce
- sub rosa
- submissively
- taut
- tense
- timidly
- timorously
- tremblingly
- tremulously
- under the breath
- under the rose
- undercover
- underground
- with breathless expectation
- with due deference
- with muscles tense
