I was thinking of keen (verb) … where keening is a long tone… 🤭 Happily it worked out nonetheless.

Anyway, on with the show!.

Tough! It scuttles backwards to a nightingale, by junkets with black stripes (7)

No, it’s not stringy.

Tough! It scuttles backwards to a nightingale, by junkets with black stripes (7)

_ a _ _ _ _ _

Charade, reversal indicator, charade

Innocent comment: I love poetry.

Not Bacchus.

Tough! It scuttles backwards to a nightingale, by junkets with black stripes (7)

_ a _ _ _ _ e

Charade (to be reversed), charade (knowledge of poetry useful here)

Yes, you have cornered it, nfs.

Tough! It scuttles backwards to a nightingale, by junkets with black stripes (7)

WORDPLAY

Tough! It scuttles [charade: crab]
backwards [reversal indicator] -> barc
to a nightingale, by junkets [charade: ode] (“Ode to a nightingale” is a famous poem by John Keats whose nickname was Junkets)

 … => barc+ode

WHOLE DEFINITION

with black stripes = barcode 

Over to you.