Men inside bend over backwards after doctor provides lubricant (5,3)

'lubricant' is the definition.
(motor oil is a kind of lubricant)

'men inside bend over backwards after doctor' is the wordplay.
I cannot quite see how this works, but
'men' could be 'or' (military abbreviation for Other Ranks) and 'or' is located in the answer.
'over' could be 'o' (cricket abbreviation) and 'o' is located in the answer.
This explanation may well be incorrect...

'provides' acts as a link.

Can you help me to learn more?