Sexual practice with an after-dark visitor (7)
I believe the answer is:
sandman
'sexual practice' is the definition.
The definition suggests a singular noun which matches the answer.
'an after-dark visitor' is the wordplay.
'after' says to put letters next to each other.
'dark visitor' becomes 'sandm' (I can't justify this - if you can you should believe this answer much more).
'an' after 'sandm' is 'SANDMAN'.
'with' is the link.
Can you help me to learn more?
(Other definitions for sandman that I've seen before include "Who could send you to sleep" , "sleep-inducing agent" , "Sender to sleep of children" , "One of the Beach Boys" , "Children's bedtime fairy" .)