Possible Clues:

• Laugh is a blast
• Thigh-slapper
• Not the sort of thing a bull would do with its horn, by the sound of it
• Funny thing (informal);bird call
• Scream, noise made by 7
• Cry of owl
• 'Give a --, don't pollute'
• Strigine call
• Minimum amount
• Topless photo session is a scream