There's a lot of laughter when a girl swallows it (8)
I believe the answer is:
hilarity
'there's a lot of laughter' is the definition.
I can't judge whether this defines the answer.
'a girl swallows it' is the wordplay.
'a girl' becomes 'hilary' ().
'swallows' is an insertion indicator.
'hilary' placed around 'it' is 'HILARITY'.
'when' is the link.
Can you help me to learn more?
(Other definitions for hilarity that I've seen before include "Gaiety" , "Great amusement" , "Laughter" , "extreme amusement" , "Unrestrained mirth" .)