Beer
A woman came home to find her retired husband waving a rolled up newspaper round his head.
Wife: 'What are you doing dear?'
Husband: 'Swatting flies - I got 3 males and 2 females'
Wife: 'How on earth do you know which gender they were?'
Husband: 'Easy - 3 were on the beer, and the other 2 were on the phone.'