Sleep with love god, taken from behind, leading to ulcer (7)

'ulcer' is the definition.
(I know that bedsore is a type of ulcer)

'sleep with love god taken from behind' is the wordplay.
I cannot really understand how this works, but
'love' could be 'bed' (synonyms) and 'bed' is found in the answer.
'god' could be 're' (Re is an example) and 're' is present in the answer.
'from' could be 'o' (I've seen this in other clues) and 'o' is found in the answer.
A single letter 's' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).

'leading to' is the link.

Can you help me to learn more?