Be dynamite, writhing between the sheets here? (7,3)

I believe the answer is:

amenity bed

I'm a little stuck... Click here to teach me more about this clue!

'between the sheets here?' is the definition.
The definition suggests a singular noun but the answer is not.

'be dynamite writhing' is the wordplay.
'writhing' is an anagram indicator.
'be'+'dynamite'='bedynamite'
'bedynamite' anagrammed gives 'AMENITY BED'.

Can you help me to learn more?

(Another definition for amenity bed that I've seen is " charge from hospital for this".)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.